13TH ASIAN REGIONAL CONFERENCE (ARC13)

PROCEEDINGS OF THE
13TH ASIAN REGIONALCONFERENCE (ARC13)
Editor: Wei Wu, Nanyang Technological University

Organizers & Partners:

INTERNATIONAL ASSOCIATION FOR ENGINEERING GEOLOGY AND
THE ENVIRONMENT (IAEG)

PREFACE
The 13th Asian Regional Conference (ARC13) of International Association for Engineering Geology and theEnvironment (IAEG) was virtually held on 16-18 November 2021 in Singapore.
The ARC series started in 1997 in Japan and has become the premium engineering geology event in Asiaand the international engineering geology community. It is held once every two years and hosted by an
Asian national group of the IAEG. Countries that have hosted the ARC include China, Korea, Japan, India,
Nepal, Indonesia, and Malaysia. ARC 13 is the first time of the ARC series held in Singapore. As Singapore
pushes for more use of underground space, engineering geology becomes increasingly important to meetthe need for more such engineering capabilities.
ARC13 was jointly organized by Society for Rock Mechanics & Engineering Geology (Singapore) and The
Geological Society of Hong Kong. The organizers offered an ideal opportunity and an online platform forprofessionals from the international engineering geology community to exchange the latest experiences andideas on engineering geology, particularly on the conference theme “Engineering Geology for Sustainable
Resource and Infrastructure Development”.
The virtual conference included 7 keynotes, 76 oral and poster presentations, and a panel discussion “Meetthe Editors of the journal of Engineering Geology and the Bulletin of Engineering Geology and theEnvironment.” Over 1000 attendees joined the keynote and parallel sessions as well as the panel discussion
during the three-day conference. The organizers thank all who were participating in the conference and all
who worked hard to make it success: authors, keynote speakers, session chairs, committee members, andall others who supported the conference. The sponsors are also thanked for their generous contributions.
Wei WuChair of Local Organizing Committee of ARC13

INTERNATIONAL ASSOCIATION FOR ENGINEERING GEOLOGY AND
THE ENVIRONMENT (IAEG)

CONTENT

ORGANIZERS & COMMITTEE MEMBERS

1

PARTNER SPONSORS

2

ABSTRACTS
T01 - Applied Geomorphology and Structural Geology

4

T02 - Soil Mechanics and Geotechnical Engineering

5

T03 - Rock Mechanics and Underground Space11

T04 - Site Investigation and Geological Model

20

T05 - Slope Stability and Landslides

22

T06 - Geohazard Engineering and Risk Assessment

27

T07 - Sensor Technology and Data Analytics in Engineering Geology

31

T08 - Energy Extraction and Storage

33

T09 - Hydrogeology and Geochemistry34

S01 - Numerical and Experimental Advances in Multiscale Failure
Analysis in Engineering Geology

35

S02 - Environment and Engineering Geophysics

39

S03 - Environmental Processes in Geotechnics

41

S04 - Engineering Geology for Tunnels and Underground Construction

42

S05 - Karst Geology and Environmental Geotechnics

46

INTERNATIONAL ASSOCIATION FOR ENGINEERING GEOLOGY AND
THE ENVIRONMENT (IAEG)

ORGANIZERS & COMMITTEE MEMBERS
LOCAL ORGANIZINGCOMMITTEE
Wei WU, Organizing Chair
Nanyang Technological University
Louis WONG, Co-Chair
The University of Hong Kong
Huei Luen ONG, Honorary Secretary
JTC Corporation
Tiong Yong TEO, Honorary Treasurer
JTC Corporation
Fiona KWOK, Member
The University of Hong Kong
Elita Yunyue LI, Member
National University of Singapore
Oskar SIGL, Members
Geoconsult Asia Singapore
Ping TONG, Member
Nanyang Technological University
Kar Winn U, Member
Society for Rock Mechanics andEngineering Geology (Singapore)

Ranjan Kumar DAHAL, Member
Tribhuvan University

Shanyong WANG, Member
University of Newcastle

Feng DAI, Member
Sichuan University

Zhijun WU, Member
Wuhan University

Jia-Jyun DONG, Member
National Central University

Fei XIAO, Member
Nanyang Technological University

Ruben DUHME, Member
Herrenknecht Asia Ltd

Zhenhao XU, Member
Shandong University

Lifeng FAN, Member
Beijing University of Technology

Shengqi YANG, Member
China University of Mining andTechnology

Anthony GOH, Member
Nanyang Technological University
Qiuming GONG, Member
Beijing University of Technology
Seokwon JEON, Member
Seoul National University
Yuyong JIAO, Member
China University of Geosciences (Wuhan)Heinz KONIETZKY, Member
TU Bergakademie Freiberg

Yokota YASUHIRO, Member
Kajima Corporation
Yaolin YI, Member
Nanyang Technological University
Jian-Hua YIN, Member
The Hong Kong Polytechnic University
Zhenyu YIN, Member
The Hong Kong Polytechnic University
Zhongqi YUE, Member
The University of Hong Kong

Mingdong WEI, Member
Nanyang Technological University

Chun Fai LEUNG, Member
National University of Singapore

Yaolin YI, Member
Nanyang Technological University

Changdong LI, Member
China University of Geosciences (Wuhan)

Jidong ZHAO, Member
Hong Kong University of Science andTechnology

Charlie Chunlin LI, Member
The Norwegian University of Science andTechnology

Zhiye ZHAO, Member
Nanyang Technological University

Xiaozhao LI, Member
Nanjing University

Rafig AZZAM, Member
RWTH Aachen University ofTechnology

Yingxin ZHOU, Member
Defence Science and Technology Agency

Bin LIU, Member
Shandong University

Scott BURNS, Member
Portland State University

SCIENTIFIC COMMITTEE

Renato MACCIOTTA PULISCI, Member
University of Alberta

Paul Chi Tak CHEUNG, Member
Geological Society of Hong Kong

Vassilis MARINOS, Member
Aristotle University of Thessaloniki

Kar-Fai LEUNG, Member
Geological Society of Hong Kong

Ki-Bok MIN, Member
Seoul National University

Huiming TANG, Member
China University of Geosciences

Haris SAROGLOU, Member
National Technical University of Athens

Faquan WU, Member
Shaoxing University

Jianping SUN, Member
China Communications Construction
Company Ltd

Jian ZHAO, Member
Monash University

Zhiye ZHAO, Scientific Chair
Nanyang Technological University
Shengwen QI, Co-Chairs
Scientific Institute of Geology andGeophysics, Chinese Academy of Sciences
Junlong SHANG, Co-Chairs
University of Glasgow
Leandro ALEJANO, Member
University of Vigo
Ismet CANBULAT, Member
The University of New South Wales
Carlos CARRANZA-TORRES, Member
University of Minnesota

Wancheng ZHU, Member
Northeastern University

ADVISORY COMMITTEE
Yingxin ZHOU, Advisory Chair
Defence Science and Technology Agency

Xuhai TANG, Member
Wuhan University
Koji UENISHI, Member
The University of Tokyo

Page | 1

INTERNATIONAL ASSOCIATION FOR ENGINEERING GEOLOGY AND
THE ENVIRONMENT (IAEG)

With Utmost Thanks & Appreciation
to our Sponsors!
Diamond Sponsors

Topaz Sponsors

Quartz Sponsors

Page | 2

INTERNATIONAL ASSOCIATION FOR ENGINEERING GEOLOGY AND
THE ENVIRONMENT (IAEG)

ABSTRACTS
Page | 3

INTERNATIONAL ASSOCIATION FOR ENGINEERING GEOLOGY AND
THE ENVIRONMENT (IAEG)

ABSTRACTSSESSION TOPIC
T01 - APPLIED GEOMORPHOLOGY AND STRUCTURAL GEOLOGY
ARC13-A-0054 - The Tsiimlyansk Reservoir Neotectonics
Ms Olga Sirotkina %#+ Lomonosov Moscow State University, Russian Federation
Ms Anna Umanskaya Free researcher, Russian Federation
Dr Igor Fomenko Russian State Geological Prospecting University, Russian Federation
Ms Dariya Shubina Russian State Geological Prospecting University, Russian Federation
Mr Denis Gorobtsov Russian State Geological Prospecting University, Russian Federation
The skipping of neotectonic studies of territories with an increasing technogenic load can lead tocatastrophic consequences.Research methods based on the relationship between the relief, the tectonic
structure and neotectonic movements provide objective material of the relief development inneotectonic time and make it possible to separate active and passive structures to identify dislocation
zones.The research was carried out in the area of the Tsimlyansk reservoir, where important
engineering objects are located power plants and the Volga-Don shipping canal. The purpose of thisresearch is to study the latest structural plan of the territory, identify active structures, the latest
deformations and determine the degree of their inheritance for planning engineering and economic
activities.For the study the structural-geomorphological method (SGM) was used. It supposes theanalysis of the relief in horizontal and vertical sections according to different-scale topographic maps.
In addition, the method of automated search for linear image elements and the calculation of theirstatistical characteristics implemented in the LESSA program was involved. The initial information was
the GMTED2010 digital elevation model with a resolution of 7.5 arc seconds. To determine the current
geodynamic activity of the region, seismic, geodetic and geophysical data have been studied.Fracture
structures according to geological and geophysical data are grouped into mutually perpendicularsystems of the diagonal and common Donbass directions.As a result of the relief analysis in the study
area the neotectonic structures of different levels were identified, coupled with "weak zones" (faults,
rocks fracturing). The identified blocks are mosaically located on the area, the main directions of theirstrike are sublatitudinal, northwestern, in the east submeridional. Ring structures and their fragments
can be seen to the west of the Tsimlyansk reservoir.The lineament analysis clearly establishes thefragmentary manifestation of regional faults. The groups of local lineaments that define the modern
relief have been found, most of them have directions from west to north and from north to east. This
direction coincides with the general direction of regional faults. Two regional lineaments were revealed,subparallel to the ancient Losev zone and structures of the Dnieper-Donets paleorift.

Page | 4

SESSION TOPIC
T02 - SOIL MECHANICS AND GEOTECHNICAL ENGINEERING
ARC13-A-0016- Experimental Study of Tight Reservoir Rock Failure Process by Acoustic Emission
Dr Shan Wu %#+ Southern University of Science and Technology, China
Prof Hongkui Ge China University of Petroleum, Beijing, China
Prof Tiantia Li Xi'an Shiyou University, China
Dr Xiaoqiong Wang China University of Petroleum, Beijing, China
Dr Ke Gao Southern University of Science and Technology, China
A fundamental problem in hydraulic fracturing is to understand the mechanism of failure process oftight reservoir rocks. Rock failure is generally caused by the propagation of fractures under the
influence natural cracks. Since acoustic emission (AE) technique has proven to be an effective tool tomonitor the dynamical fracture propagation, here, AE is employed to investigate the different rock
failure processes under uniaxial compression. The experiment rock samples are sampled from fourtight reservoirs in typical oil and gas production fields in China. The C7 and LCG tight sandstone arerespectively collected from the Ordos Basin and the Junggar Basin. Both the LJP shale and LMX shale
are obtained from the Sichuan Basin but with different formations. We analyze the characteristics ofacoustic emission data and discuss the relation between acoustic emission parameters and the rock
failure process. The results demonstrate that on experimental scale the natural fractures contained inthese rocks have distinct impacts on fracture propagation. The AE rate curves indicate different failure
patterns, and the RA-AF (RA value and Average Frequency) values of AE reveal that the final shear
failure is caused by tensile fracture accumulation. For the vertical-bedding samples, we barely observe
shear phenomena accumulated by tensile cracks. While for the parallel-bedding samples, it is common
that the tensile cracks could gradually accumulate into shear failure. Additionally, the b-value before
the final failure is closely related to the natural crack activation, and the b-value during the final failure
signifies the complexity of the fracture network. The b-value could reflect the formation of the fracture
network under the joint effects of stress and natural cracks. Specifically, in stress dominated failure
process, the b-value is high before the final failure and decreases thereafter. When the failure iscontrolled by both the natural cracks and stress, the b-value is low before the failure and increases after
that. While when the natural cracks dominate the failure process, the b-value is generally within a low
level during the whole procedure .

ARC13-A-0035-An Experimental Study On The Effect Of Waste Tire Rubber Particles On Shear
Strength Characteristics Of Loes
Mr Rongsen Zhu %+ Northwest University, China
Prof wan-li xie # Northwest University, China
Ms Hui Yang Northwest University, China
With the development of automobile industry, the detriment of waste tires to human beings and theenvironment is gradually increasing. How to deal with them harmlessly or even make rational use ofthem has become a global concern. The purpose of this paper is to explore the influence of waste tirerubber particles in improving the geotechnical characteristics of loess, and discuss the possibility of its
application in slope engineering and subgrade engineering. Taking the particle size and content ofrubber particles as variables, a series of ring shear tests were carried out on loess samples mixed withrubber particles. According to the shear strength of soil samples under various combinations, theoptimal selection under different working conditions was obtained. In addition, scanning electron

Page | 5microscope (SEM) and computed tomography (CT) scanning tests were used to analyze themicrostructure of the samples, including the contact relationship between rubber particles and soil
skeleton particles, and the effect of rubber particles on the change of pore type, so as to explain themacro behavior of soil from the micro point of view.

ARC13-A-0038-Mechanics Characteristics And Microstructure Evolution Of Fiber-reinforced
Collapsible Loess From The Chinese Loess Plateau
Ms Hui Yang %+ Northwest University, China
Prof Wanli Xie # Northwest university, China
Dr Rongsen Zhu Northwest University, China
The porous structure of loess can not be eliminated fundamentally by banded and mesh reinforcement
materials. Fiber as homogeneous material with holistic structure and isotropy. Fiber-reinforced loess is
widely used to achieve three-dimensional reinforcement technology, especially polypropylene fiber(PP fibers) reinforced materials. In this paper, polypropylene mesh fiber and rod fiber are selected as
the improved reinforcement materials for collapsible loess from the Chinese Loess Plateau. The effectsof the two fibers on the mechanics characteristics of the stiffened loess were investigated by triaxial
tests. Fiber length and fiber incorporation amount were selected as control variables to study the
optimal fiber length and fiber incorporation amount to effectively improve the strength of collapsible
loess. Samples before and after triaxial tests were selected for further scanning electron microscope(SEM) and computed tomography (CT) scanning tests. The interaction between loess and different
polypropylene fibers was investigated from the microscopic point of view, that is, the microstructure
evolution characteristics of soil-geosynthetics interaction. The strengthening mechanism of PP fibers
on collapsible loess strength is clarified, and the optimal scheme of fiber-reinforced soil is determined.
The microstructure evolution characteristics showed that the PP fibers can effectively reduce theporosity of loess.

ARC13-A-0069-Effect of Initial Water Content and Dry Density on Soil Water Characteristics ofCompacted Soil
Ms Yu Wang %#+ Chang’an University, China
In order to investigate the effect of initial water content and dry density on the soil water characteristicsof the compacted soil, the loess used as filling in the Land-making Project of Yanan new district inChina was collected and compacted to two series of samples: one is the same dry density but different
initial moisture content, the other is the same initial moisture content but different dry density. The
SWCCs of all samples in the range of 0 ~ 105 kPa were measured by the filter paper method. The
measured data are fitted with the Fredlund; Xing equation for each dry density. For the samples withdifferent initial water content, the SWCCs show significant differences in the range of 100 ~ 1000 kPa:
the retention capacity of water will increase with the initial water content below the range of plastic
limit. For the samples with different dry density, The SWCCs show prominent differences in the suction
range below 100 kPa while overlapping above this suction. Those suggest that SWCCs of compacted
soil with the same dry density are not exactly the same, the effect of initial water content should beconsidered; and the SWCCs in the high suction range are independent on dry density of compacted
soils with the same initial water content, while correlated in the low suction range. This study provide
support for further investigation on the unsaturated behaviors of the compacted soil.

Page | 6

ARC13-A-0072-Stress-strain, suction variation and critical state characteristics of Q3 undisturbed
loess under constant water content
Mr Lin Zhang %#+ Chang'an University, China
Prof Tonglu Li Chang'an University, China
Ms Cunli Chen Xi'an University of Technology, China
Ms Yan Li Chang'an University, China
Constant moisture content is an important aspect of geotechnical engineering tests. In order toinvestigate the stress-strain，suction change and critical state characteristics of Q3 undisturbed loessfrom Lanzhou, China under constant water content, the GDS unsaturated triaxial instrument with
controllable drainage conditions was used, and the pore-water pressure, axial stress and strain of theundisturbed loess with different initial suction during the isotropic compression and triaxial shear tests
were measured. The analysis of the test results shows that: the greater the initial suction of the isotropic
compression test, the smaller the compressibility and the greater the degree of suction reduction; thegreater the isotropic stress, the greater the degree of saturation increase; the stress-strain curve of
triaxial shear test is hardening type, the deviator stress has little effect on the decrease of suction, andmainly affects the increase of saturation; the critical state lines of undisturbed loess with different initialsuction in q-p plane are parallel straight lines, and the critical state line of deviator stress and effective
average stress can be expressed uniquely by the critical state line of saturated soil; with the increase of
the initial suction，the critical state lines of unsaturated soil in e~lgp' plane moves up parallel，and therelation between their intercept and the initial suction is hyperbolic, the slope of the critical state line ofsaturated soil in e~lgp' plane is obviously smaller, nevertheless the relationship between the ratio ofcritical void ratio of unsaturated soil (under different initial suction) to saturated soil and failure
saturation (or gas saturation) can be expressed by a normalized exponential function.

ARC13-A-0077-Microscopic Deformation Analysis of Unsaturated Loess with an Extended
Discontinuous Deformation Analysis Method
Mr Qiang Li %#+ Chang'an University, China
Prof Tonglu Li Chang'an University, China
Using numerical method to investigate the micro property of unsaturated loess is helpful for theunderstanding of its physical mechanical behavior. However, some obvious differences were observed
between the microstructure constructed by the existing numerical models and the real microstructureof loess, and it is very challenging for these existing models to take consideration of the change on thehydraulic property of the soil produced by deformation. Therefore, we try to establish a model toconsider the microstructure of loess and the capillary force based on the discontinuous deformation
analysis (DDA). In our model, four key steps are adopted in the construction process of the
microstructure of loess. Firstly, a shape database was constructed based on the geometries of a large
number of skeleton particles of loess. Secondly, some particles were selected from the shape databaseaccording the particle size distribution curve of loess. And then，these particles are dropped into asample box. Finally, the capillary force at certain water content is calculated according to the YoungLaplace equation, and applied on the wetted surface of two adjacent particles based on extending DDA.
This model was used to conduct confined compression numerical tests on loess with three different
water contents, and the simulated result is compared with the experimentally measured compression
curve to validate the method. Moreover, the model reflects the micro evolution of pore during thecompression of unsaturated soil. The soil deformation at micro-scale is majorly generated by large
pores; the deformation pattern is concerned with the moisture, namely, the pores are mainly shrunk at
low water content while mainly disintegrate at high water content. This research proposed a newnumerical model to explore the mechanism of deformation behavior of unsaturated loess.

Page | 7

ARC13-A-0117-Tests on Mechanical Behavior of Cement-treated Masado Under the Influence ofAcidic Environment and Temperature
Mr Peng PENG %#+ Nagoya Institute of Technology, Japan
Prof Feng ZHANG Nagoya Institute of Technology, JapanDr Hiromasa IWAI Nagoya Institute of Technology, Japan
Mr Ittetsu OHARA Nikken Sekkei Civil Engineering, JapanMr Keigo TAKAGI Nagoya Institute of Technology, JapanMr Tomoya IWATA Nagoya Institute of Technology, Japan
Cement-treated Masado (CTM), as a common cement-mixed geomaterial, is usually only used inground improvement for temporal structures in Japan. However, in recent years, it has been used for
newly constructed permanent structures, such as the supporting ground of pile foundations and direct
foundations. The long-term stability of CTM has not been thoroughly investigated, since that it has therisk of exposure to changes in acid environment and temperature, which are very common in volcanic
areas in Japan. In this study, to investigate the influence of acidic environment and temperature on themechanical behavior of CMT, a systematic test program using triaxial tests was conducted on CMT
specimens under different conditions of acidic environments, temperatures, and confining pressures.
To avoid the extra influence of water on the mechanical behavior of CMT, a special double-cell was
designed within the pressure chamber of the triaxial loading device, so that the volumetric strain of thespecimens completely sealed with gum sleeve can be accurately measured in triaxial compression andcreep tests. Combined with the influence of the initial confining pressure, the influence of the acidic
environment and temperature on the strength and dilatancy of CMT is carefully investigated. In
addition, the chemical components of all the tested specimens are investigated by X-ray fluorescence
spectrometry analysis to identify the calcium leaching in the curing period. Based on the test results, a
relation between the stress ratio at the critical state and the influential factors, including the initialconfining pressure, acidic environment and temperature, is proposed by regression analyses.

ARC13-A-0124-Creep Behavior of Intact Loess Followed Unloading Paths
Mr zhenxiao li %#+ Northwest University, China
Several high-fill projects are carried out on the Loess Plateau, China, accompanying the progressive
failure of slopes due to excavation. The compelling need requires a deep understanding of variation in
the creeping behaviors of intact loess exposed to unloading. A series of creep tests of intact loess were
performed under two separated unloading paths: decrease in confining pressure at constant deviator
stress and decrease in confining pressure at axial stress. The results demonstrated that axial
deformation followed the first unloading path always appears as compression. While the three formsof axial deformation followed the second path, depending on the applied axial stress level. At a low
unloading stress level, the elongation of axial deformation was observed. At a relatively unloading
stress level, the axial deformation of the soil experienced the first elongation and then compression. At
a high unloading stress level, the axial deformation appeared as compression, and finally, failure
occurred with the increase of the unloading stress level. The failure approach index was introduced touse as the criterion for the loess to transform from stable to accelerated creeping. Finally, a modified
Burgers model was proposed to characterize the creeping behavior of intact loess followed unloading
paths. There was a good comparison between the calculated and measured data of the soil that
establishes the rationality and validity of the proposed model.

Page | 8

ARC13-A-0138-Circular Shaft Construction Using Vertical Shaft Sinking Machine (VSM) in
Singapore’s DTSS2 Project%#Dr Aung Ko Ko Soe DTSS2 Department, National Water Agency, PUB, Singapore
Ms Lai Lynn Woo DTSS2 Department, National Water Agency, PUB, Singapore
Mr Cheng Boon Ng DTSS2 Department, National Water Agency, PUB, Singapore
Ms Angela Ong DTSS2 Department, National Water Agency, PUB, Singapore
Mr Venkatesa Perumal DTSS2 Department, National Water Agency, PUB, Singapore
Mr Guo Hao Lim + DTSS2 Department, National Water Agency, PUB, Singapore
Shaft constructions are required in the Deep Tunnel Sewerage System Phase 2 (DTSS2) project at
designated locations along the tunnel alignment for the launch and retrieval of Tunnel Boring Machines(TBM) and for the operation and maintenance of the used water conveyance system. Some of the shaftsin the upstream stretch of the tunnel are to be constructed in heavily built-up urban areas. Therefore,
shaft excavation sites are bounded by commercial/residential buildings, schools, hospitals,
transportation infrastructures, major utilities services etc. In addition, hydrogeological profiles at shaft
locations are challenging due to the presence of soft clay layers, permeable soil and highly tomoderately weathered fractured rock along the depth of excavation horizon. Hence, it is very likely tocause surrounding ground to settle and overstress the foundation system of the existing structures inclose vicinity if ground water level draws down or pore pressure drops due to seepage flow into theshaft or stress relief despite a good ground water management system is put in place. Since these
existing structures/services are very sensitive to ground movement, it is of paramount importance tokeep construction impact and associated geotechnical risks to a minimum. Since shaft excavation by
Vertical Shaft Sinking Machine (VSM) has proven advantages and benefits over conventional shaft
excavation methods, especially with rapid sinking rates and maximum safety and environmental
control, the VSM method is proposed to construct five of the shafts in Contract T-11 of DTSS2 Project.
This is the first known use of VSM for shaft construction in Singapore and currently 3 out of 5 shafts
have been successfully constructed with this technology. This presentation outlines the background of
the method used and intends to share the design approach, challenges encountered, benefits gained,
and lessons learnt based on DTSS2 experience.

ARC13-A-0141-Geotechnical and Leaching Characteristics of Marine Clay-cement-incineration
Bottom Ash Mixes
Mr KAI GUO %#+ Nanyang Technological University, Singapore
Prof Wei Wu Nanyang Technological University, Singapore
A huge amount of incineration ash is generated daily from municipal solid waste (MSW) incineration
plants worldwide. In Singapore, most of the incineration ash is disposed at Semakau Landfill, whose
capacity cannot meet our increasing demand of waste disposal. This study reports a method to use
MSW Incineration Bottom Ash (IBA) as a partial replacement of the ordinary Portland cement in deep
cement mixing for soil improvement. We investigate the geotechnical and leaching properties of soilcement-IBA mixes and assess the toxic element concentrations in dry mixes and groundwater. Our
results show that this method is feasible in terms of uniaxial compressive strength, leaching
concentrations of heavy metals and other elements, as well as estimated toxic element concentrations
in dry mixes and groundwater. The partial replacement of the cement with IBA slightly reduces theshort-term strength of the IBA and cement treated soil but slightly improves the long-term strength.
The heavy metals can be immobilized effectively in the solidified soil-cement matrix. The reduction in
the short-term strength is due to an increase in total porosity with higher IBA content, while the growthin the long-term strength is related to an increase in gel porosity associated with hydration reaction.
This method is possible to offer an alternative safe IBA disposal and meanwhile to reduce thedependence on imported cement in resource scarce countries (like Singapore).

Page | 9

ARC13-A-0163-A Coupling Method of Distinct Lattice Spring Model and Beam Finite Element
Model for Collapse and Stability Analysis of Foundation
Mr Zhe Li %+ Tianjin University, China
Prof Gao-Feng Zhao # Tianjin University, China
In this work, the distinct lattice spring model (DLSM) is further developed for handling geotechnicalproblems. The DLSM is proposed for analyzing material failure and crack propagation. The DLSM is akind of discrete element method, it represents materials by a system of discrete particles interacting via
springs, can naturally predict deformation and collapse of soil correctly without any special operation.
To ensure safety, supporting structure is widely applied to resist large deformation of soil. However,the dimension scale of the supporting structure is usually much smaller than it of soil. It;s unsuitablefor DLSM to directly analyze structure and soil together as a full 3D model. Therefore, the structuralelement, beam finite element, is adopted to model the structure. Meanwhile, a method to couple the
DLSM and the beam is developed. The beam has 6 degrees of freedom (DOF), 3 DOFs for displacements
in x, y, and z axes, and 3 DOFs for rotations around x, y, and z axes. In DLSM, only 3 displacement
DOFs are used. To solve this mismatch, one beam node connects to several DLSM particles interacting
via normal springs. The cross-section features of the beam are considered in this model. The coupling
method is based on the translation of force, the bending moment transfer is handled by the coupling
method as well. Based on this coupling method, the cross-section naturally affects the interaction
without any other redundant operations. The central difference method is used in the beam integration,
which is the same as that in the DLSM. The beam and the coupling method get verifications via someclassical boundary value problems. The results show that the algorithm has good accuracy androbustness.

Page | 10

SESSION TOPIC
T03 - ROCK MECHANICS AND UNDERGROUND SPACE
ARC13-A-0001-Seepage Analysis for Rock Tunnel Construction Based on Analytical Methods
Dr Jianping Sun %#+ CCCC-SJ PTE LTD, Singapore
Ms Lanting Wu China Communications Construction Company Limited (Singapore Branch), Singapore
Rock tunnel/cavern excavation involves high risk of unforeseen ground conditions. One of the risks isthe chance of hitting the water bearing zone. And rock grouting is considered as the most efficientmethod to reduce the water inflow. To determine whether rock grouting is needed, the probing should
be carried out first. If the expected water inflow from probe hole is larger than the allowable maximum
water inflow, the grouting will be carried out to achieve the strict requirement on the water inflow.
After grouting, check hole(s) will be drilled on the same face and same length as the grouted hole. If
water inflow is still higher than threshold value, grouting procedure will be repeated until to achieve
the grout target. Although many researchers conducted studies related to water flow into subsea tunnel
and rock grouting, the knowledge on the practical execution is still limited. Based on other researchers;
work, the analytical solutions of water flow for each step of subsea tunnel construction (i.e. probe hole,tunnel before grouting, tunnel after grouting and check hole) have been derived.;Based on the study
on these analytical solutions, the key findings are summarized as below: 1. The variation of water flowin probe hole is within 3% when the probe hole diameter increases from 48mm to 60mm, which means
there is little influence of probe hole diameter change on the water flow into the probe hole. 2. The
variation of water flow into probe hole can be up to 25% when the water pressure in probe holeincreases from 0m water head to 12m water head, which means it is important to measure the waterpressure and water flow quantities simultaneously. 3. There is a linear relationship for the water flow
between probe hole and tunnel, which tally with the actual practice. 4. Decreasing the permeability of
the grouted zone contributes to a decrease of the water inflow. However, when the permeability of thegrouted zone decreases to a certain value, the water inflow is no longer decreased significantly, whichtally with the practical experience.

ARC13-A-0012-Fracture Process Zone Features of Three Granites Under Mode I Loading: Insightsfrom Acoustic Emission and Thin-section Observation
Dr Tianyang Guo %#+ The University of Hong Kong, Hong Kong SAR
Dr Louis Wong The University of Hong Kong, Hong Kong SAR
Ms Xinyu Xiao The University of Hong Kong, Hong Kong SAR
Fracture process zones (FPZs) often develop in front of crack tips preceding the initiation ofmacrocracks subjected to loading in rocks. However, the effects of mineralogy and texture of granites
on the FPZ features are very complex and not entirely understood. In this study, we experimentally
study the FPZ features of three granites of comparable mineral composition, but with different grain
sizes, namely fine-, medium- and coarse-grained granites (gf, gm, and gc respectively) in mode I semicircular bending tests. The development of FPZs is monitored by continuously recording the acoustic
emission (AE) during the test. The fully-developed FPZs (FD-FPZs), which refer to the FPZ status
immediately before the initiation and propagation of macrocracks, are characterized by the spatial
distributions of AE events. To investigate the microcracks features, a postmortem microscopic study isconducted on the thin-section samples of the specimens after loading tests quantitatively. The results
show that for the FD-FPZs of the gf and gm, the AE event number decreases exponentially with the
distance away from the notch central plane along the principal tension stress direction, and the AE
event number decreases nonlinearly with the distance for the gc. The locations of the maximum AE
event points are consistent with those of the maximum microcrack density along the same direction for
the gm. In terms of the energy distribution of the AE events characterizing the FD-FPZs, the gf isPage | 11comparable with that of gc, which is different from the energy distribution of the gm. This experimental
study reveals the complex effects of mineralogy and texture on the FD-FPZ development of granite
under mode I loading.

ARC13-A-0063-Evaluation Framework of Underground Space Resources of a Costal Soft Soil City:
with Shangha as an Examplei
Prof Wang Jianxiu %#+ Tongji University, China
Prof Yujin Shi Shanghai Institute of Geological Survey, China
Prof Hanmei Wang Shanghai Institute of Geological Survey, China
Dr Xiaotian Liu Tongji University, China
Dr Yansheng Deng Tongji University, China
Mr Qiwei Gu Tongji University, China
Mr Daping Chen Shanghai Institute of Geological Survey, China
Multi-layers interbedded with sand, silt, clay and clayey soil are symbols of many coastal cities, suchas Shanghai. Multi-aquifer multi-aquitard system is formed under the geological conditions. Soil andsediment with different depth and different lithology type fit for different purpose. How to evaluate
the quantity and quality of the underground space is vital for the urban sustainable development. With
Shanghai as an example, the evaluation frame work including both quantity and quality evaluation
method is suggested. Quantity evaluation system considering developed and utilized resources, non
exploitable resources, partially exploitable resources and fully exploitable resources was established.
Quality evaluation system considering structural stability, engineering geological condition,hydrogeological condition, geological hazard, building height, development depth, undergroundresources were established. Finally, with Chenghuangmiao Temple strict as example, the evaluation
frame was used and checked to provide reference for future city underground space plan.

ARC13-A-0074-Determination of on Fracture Toughness of Mode I Fractures from Three-point
Bending Tests at Elevated Confining Pressures
Dr Hongwei Yang %#+ Sun Yat-Sen University, China
Prof Jörg Renner Ruhr-Universität Bochum, Germany
Dr Michael Krause Geomecon GmbH, Germany
Fracture toughness is one of the key parameters for the characterization of brittle rock fracturing. Yet,
constraints on it mainly rest on measurements performed at ambient pressure, although rock fracturing
frequently occurs at elevated pressures even in geotechnical applications. To address the lack of agenerally accepted evaluation procedure for tests at elevated pressure we explored the conditions for
initiation and propagation of mode I fractures in samples subjected to bending at elevated pressure bynumerical modelling and analytical considerations of the involved angular moments. We derived anevaluation procedure and applied it to experimental observations for specimens with either a chevron
or a single-edge notch of four different rocks (a granite, a limestone, a marble and a sandstone)
subjected to three-point bending at confining pressures up to 30 MPa. Two sealing methods wereconsidered. Specimens were either varnished or jacketed by a rubber tube, differing in whetherpressure is allowed to build up inside the pre-fabricated notch or not, respectively. Irrespective of notchgeometry and sealing method, the determined toughness values increase significantly with confiningpressure. The apparent toughness determined for jacketed specimens is, however, larger than that forvarnished specimens, for which toughness seems to reach a plateau with increasing pressure. The
similarity of the pressure dependence of the toughness determined for varnished, i.e., uniformly
pressurized, samples with that of other physical properties suggests that it is controlled by the closureof pre-existing micro-cracks; the absence of pressure dependence beyond some tens of MPa suggests

Page | 12

that non-linearity effects may not be as severe at depths beyond a few kilometres as previously
discussed. Our study points to the necessity of resolving numerical issues associated with compressed
fractures and of further improving experimental facilities for the determination of fracture toughness
at elevated pressure.

ARC13-A-0108-The Influence of JRC and Surface Geometry on the Mechanical/Hydraulic Apertureof 3D Printed Joints
Mr Tan-Minh Le %+ Rock and Soil Mechanics Laboratory, Graduate Institute of Applied Geology, National
Central University, Taiwan
Prof Jia-Jyun Dong # Graduate Institute of Applied Geology, National Central University, Taiwan
We conducted discontinuity logging and estimated Geological Strength Index (GSI) of the NeogenePaleogene sedimentary and the Cretaceous igneous rock core samples taken for an offshore wind farmproject off the Kyushu (Southwest) region in Japan. Bottom-fixed foundations, namely jacket typefoundations are planned for wind turbines. Whilst there have been few cases where the GSI system isapplied to onshore projects as well as offshore projects in Japan, we attempted to employ the GSI system
to characterise the rock foundation for offshore wind farms instead of Japanese conventional rock massclassification system proposed by Central Research Institute of Electric Power Industry (CRIEPI). This
study compares the GSI values estimated from different approaches with Rock Mass Rating (RMR)
calculated based on Bieniawski (1989) and the CRIEPI rock mass class to discuss the applicability of thequantitative GSI system to offshore wind projects in Japan. The rock mass strength and deformation
modulus were calculated from the estimated GSI values and unconfined compressive strengths (UCS)
obtained by laboratory tests on intact rock based on the Hoek-Brown criterion. We propose aquantitative approach of GSI = 90/70 x (R2+R3+R4) - 5, modified from Song et al. (2020), where R2, R3
and R4 are the ratings for RQD, the spacing of discontinuities and the conditions of discontinuities
respectively in the RMR system since it has a good correlation with qualitative GSI values. The GSI
values generally range from 25 to 70, which are equivalent to the range of 35 to 80 in RMR values. The
GSI values of each CRIEPI rock mass class generally agree with the typical ranges suggested by Cai etal. (2002); however, the estimated GSI values tend to be larger. Whilst equivalent Mohr-Coulomb
friction angles derived based on Hoek et al. (2002) tally with a typical range presented by Yoshinaka etal. (1989), equivalent Mohr-Coulomb cohesive strengths vary in a wide range depending on UCS. The
rock mass deformation moduli estimated based on Hoek and Diederichs (2006) correspond with thoseobtained by pressuremeter tests.

ARC13-A-0099-Comparison of Different Approaches of GSI System Applied to Foundation Design
for Offshore Wind Farm in JapanMr Tomohiro Yasuda %#+ Kiso-Jiban Consultants Co., Ltd., Japan
Mr Koki Kimura Kiso-Jiban Consultants Co., Ltd., JapanMr Tatsuya Koizumi Kiso-Jiban Consultants Co., Ltd., JapanMr Masahiko Hamada Kiso-Jiban Consultants Co., Ltd., Japan
Fluid flow through rock mass is a critical issue for rock engineering practice and geoscience fromshallow to great depth. Among others, the hydraulic aperture (e) of a single joint is a key variable forpredicting hydraulic conductivity. Usually, the mechanical aperture (E) of rock joints under different
normal stress can be predicted via famous Barton model. If the relation between mechanical andhydraulic apertures is available, the hydraulic aperture at different depth can thus be calculated. In thisstudy, laboratory measurements of mechanical/hydraulic apertures of sawed, polished aluminum
samples using gas flow via YOKO 2 system under a confining stress from 3 MPa to 120 MPa wereconducted. Different from the widely adopted normal displacement method for measuring the joint

Page | 13

closure, we measured the mechanical aperture from the joint volume divided by joint area, directly.
Based on the measurements, we found the relationship between hydraulic and mechanical apertures is
non-linear. The traditional assumption of linear relation between mechanical and hydraulic apertures
could not be valid under a wide spectrum of confining stress, even for a smooth joint. Our measurementshows a contradict trend to the widely used non-linear relation between E/e and e. We argue that theestimation of initial aperture for converting joint closure curves into mechanical aperture for normal
displacement method accounts for the contradict trend. Joint apertures (e and E) cannot totally closeeven when the effective normal stress goes up to 120 MPa (~5 km). The residual hydraulic andmechanical apertures of smooth aluminum joint are about 1416 &micro;m and 33-37 &micro;m,respectively. Finally, we demonstrated clearly that the influence of matrix (intact rock) pore volume on
joint volume measurement is significant even for low porosity granite sample (porosity &lt; 1%) andthe matrix permeability contributes few to the measured hydraulic aperture.

ARC13-A-0105-The Relation Between Hydraulic and Mechanical Apertures of Smooth Joint Under
Low to High Confining Pressure
Mr Xuan-Xinh Nguyen %#+ Graduate Institute of Applied Geology, National Central University, Taiwan
Prof Jia-Jyun Dong Graduate Institute of Applied Geology, National Central University, Taiwan
Characterizing rock joints' hydro-mechanical behavior is critical for rock engineering because joints
frequently act as weak planes and fluid paths of the rock masses. Among others, joint roughness
directly controls the mechanical and hydraulic behaviors of rock joints. The Joint Roughness Coefficient(JRC) has been widely used to quantify the joint roughness for four decades. This parameter wasincorporated into empirical equations to predict the joint closure under stresses and fluid flow
characteristics as well. However, the validity of using one single parameter to represent the complex
geometry of joint surface could be an interesting topic to be explored. This study creates numerous
smooth joint samples (including matched and mismatched joints) with similar JRC (2-4) but different
surface geometry via 3D printers. The mechanical and hydraulic apertures (E and e) of the printed joint
samples under different normal stress were measured using high confining stress,
permeability/porosity measurement system (YOKO2). The relation between joint closure (related to E)
and fluid flow characteristics (related to e) can be quantified. The testing results show a significant
influence of joint surface geometry on the E-e relation; even the JRC is roughly the same. The role ofgeometry heterogeneity of real rock joint surface on the hydro-mechanical coupling needs further
study.

ARC13-A-0119-DEM Simulation Of Transversely Isotropic Rocks Under True Triaxial StressCondition
Mr Saad Faizi %#+ The University of Hong Kong, Hong Kong SAR
Dr Chung Yee Kwok The University of Hong Kong, Hong Kong SAR
Dr Kang Duan Shandong University, China
The response of transversely isotropic rocks under true triaxial testing is studied using the discreteelement method (DEM). Numerical rock specimens of four different orientations of beddings (i.e.
&beta; = 0o, 30o, 60o, 90o) are created and three series of test simulations (i.e. &sigma;3 =10, 50, 100MPa) are conducted on each of the rock models, with five different values, ranging from &sigma;2=;&sigma;3;to &sigma;2;=&sigma;1;stress states. The impact of the bedding orientation and theintermediate stress on the peak strength and degree of anisotropy are subsequently explored andexplained through underlying micromechanics. An ascending then descending variation of the peakstrength, in form of a fan-shaped; curve, is noted against &sigma;2. The initial ascend is because of theincrease in stress asymmetry, reducing the number of failure planes, as well as the suppression ofPage | 14

sliding of weak planes, while the strength eventually descends as &sigma;2;becomes large enough to
induce cracks in the pre-peak region. Similarly, varying degrees of tilting; of the fan-shaped curves forthe different bedding orientations are noted. This is owing to the difference in the degree of suppressionof the weak plane slippage, indicating the effect of &beta; on peak compressive strengths. The U-shaped
variation of peak strength with anisotropy angle is also observed that flattens under higher&sigma;2;values, due to the suppression of the slipping of weak planes, indicating the reduced effects
of anisotropy when &sigma;2;is increased. For numerical models of Posidonia Shale under&sigma;2;normalized by &sigma;*, which is the conventional triaxial compression strength obtained
for &beta; = 0o at a specific state, the anisotropy effect, in fact, ceases to influence when &sigma;2;/&sigma;* is higher than 0.76. This study, hence, provides a comprehensive understanding of themechanical behavior of anisotropic rocks under polyaxial stress conditions. The data and findings fromthis study can be utilized in not only evaluating the effectiveness of various proposed failure criteria
but also modifying or formulating a new failure criterion for rocks that can model the effects of bothpolyaxiality and anisotropy together.

ARC13-A-0125-Thermal Effects on Heterogeneity and Anisotropy of Spatial Distribution of
Microcracks in Granite
Mr Jingwei Gao %+ Beijing University of Technology, China
Mr Lifeng Fan # Beijing University of Technology, China
The rock is subjected to thermal action in high-temperature rock engineering. The thermal action
induces the generation of microcracks in rock due to the differences in thermal expansion properties ofminerals. Quantitative characterization of microcrack characteristics is important for understanding thethermally induced deterioration mechanism of rock properties. The parameters, such as length, width,area, volume and porosity, were generally introduced to quantitatively describe the microcrack
characteristics in previous studies. To further quantitatively describe the spatial distribution
characteristics of the microcracks, in the present study, two indexes (heterogeneity coefficient andanisotropy coefficient) were proposed based on the micromechanics Computed Tomography (CT)experiment. The two indexes were used to quantitatively describe the heterogeneity and anisotropy ofspatial distribution of microcracks. Moreover, the effects of heating temperature (from 25 to 1000
&deg;C) and thermal cycling number (from 0 to 16 times at 500 &deg;C) on the heterogeneity coefficientand anisotropy coefficient were further discussed. The results show that both the heterogeneity andanisotropy of thermally treated granite increase to their maximums as temperature increases to 500&deg;C and then significantly decrease to constants as temperature further increases. For the specimens
subjected to thermally cycling treatments at 500 &deg;C, both the heterogeneity and anisotropy increasesignificantly after the first thermal cycle, after which the heterogeneity and anisotropy change slightly
as the cycling number further increases. The proposal of the heterogeneity coefficient and anisotropy
coefficient realizes the quantitative characterization of the spatial geometric characteristics of the
microcracks.

ARC13-A-0126-Investigation of Stress Wave Propagation Through Rock Masses with Double-scale
Discontinuities by a Split Three Characteristic Lines Method
Ms Meng Wang %+ Beijing University of Technology, China
Mr Lifeng Fan # Beijing University of Technology, China
Mr Qihao Yang Beijing University of Technology, China
The study of stress wave propagation in natural rock masses is significant for the dynamic stability ofrocks. Discontinuities ranging from micro-defects to macro-joints are widely existing in natural rockmasses, which have a significant effect on stress wave propagation.Currently, the traditional methods

Page | 15

have been successfully applied to stress wave propagation through single-scale discontinuous rockmasses. The stress wave propagation through the macro-jointed rock masses can be solved by the two
characteristic lines method combined with the displacement discontinuity model (DDM). In addition,practical rock masses are generally micro defected, which can be equivalently described by aviscoelastic medium. The traditional three characteristic lines method was developed to solve the stresswave propagation through the micro-defected rock mass. Because the effects of micro-defects andmacro-joints in rock mass on stress wave attenuation of velocity and amplitude are different in themechanism. Therefore, it is still difficult to analyze the stress wave propagation through double-scalediscontinuous rock masses containing micro-defects and macro-joints. To solve the stress wave
propagation through rock masses with double-scale discontinuity, a split three characteristic lines
method combined with DDM was proposed in the present study. The three characteristic lines are split
at the location of a single macro-joint. So that the split three characteristic lines are divided into threebasic elements: triangle, diamond, and separated diamond elements. Similar to the traditional threecharacteristic lines method, the triangle, and diamond elements are used to solve stress wave
propagation at left boundary points and ordinary interior points of the rock mass. To further study thestress wave propagation at the macro-joint, the separated diamond element is proposed. The DDM isintroduced into the separated diamond element to solve wave propagation at pre-interior points andpost-interior points of the macro-joint. The results show that the present method can be used toinvestigate the stress wave propagation through double-scale discontinuities efficiently.

ARC13-A-0147-Measuring the Mechanical Parameters of Fragmented Earth and Asteroid Rocks
with Micro-rme
Prof Xuhai Tang %#+ Wuhan University, China
Mr Yiheng Zhang Wuhan University, China
Ms Jingjing Xu Wuhan University, China
Dr Adriana Paluszny Faculty of Engineering, Department of Earth Science & Engineering, Imperial College
London, United Kingdom
Prof Quansheng Liu Wuhan University, China
Measuring the mechanical property of rocks accurately is critical, however, in many situations, it ischallenge to obtain intact and standard rock specimens required by macroscale rock mechanics
experiments (macro-RME), such as MTS tests. For example, the rocks are frequently fragmented andmuddy inside faults, which leads to the difficulty of drilling and sampling. The phenomenon of core
disking also widely exist due to high-stress. Additionally, the future extraterrestrial human activities,
such as resources exploitation and base construction on Mars, need the aid of geotechnical engineering
technology. Currently, there are only two approaches for humans to obtain the rock samples beyond
Earth: sample-return activities by spacecraft and meteorite investigation. Meteorites are rare,
expensive, small in size and arbitrary in shape, so it is difficult to process them into standard rocksamples required by traditional macro-RME. In this paper, a technique is developed to measure themechanical property of small and any-shaped rocks based on microscopic Rock Mechanics Experiments(micro-RME), in order to investigate granites and NWA13618 meteorites. First, using nanoindentation
tests, the elastic modulus of rock-forming minerals is measured. Then, with the results of micro-RME,
the upscaling modelling method is developed to get the macroscale mechanical property of these rocks.

Page | 16

ARC13-A-0151-Estimating the Mechanical Properties of Complex Fractured Rock Masses Using
Machine Learning%+
Mr Wenzhao Meng Nanyang Technological University, Singapore
Prof Wei Wu # Nanyang Technological University, Singapore
Natural rock masses contain randomly distributed fractures and exhibit complex mechanical behaviors.
These fractures may interact with filling materials (e.g., soil, water, and ice) and behave even more
complex. The estimation of fracture parameters in present failure criteria is often subjective and may
not be reliable to predict the mechanical properties of fractured rock masses. Here, we present a random
forest model to predict the mechanical behaviors of granite specimens with ice-filled fractures. Due todifficulties in collecting fracture parameters from invisible granite in the laboratory and the field, we
employ a two-dimensional particle flow code model and validate this model using the uniaxial
compression test results of intact and fractured granite specimens. The numerical results show that thepersistence factor and the inclination angle significantly influence the uniaxial compression strengthand the Young;s modulus of the frozen fractured specimens, while the influences of the fracture number
and the ice layer thickness are less important. We collect the uniaxial compressive strength and theYoung;s modulus from 186 uniaxial compression tests on the frozen fractured specimens with different
ice layer thicknesses, inclination angles, persistence factors, and fracture numbers. We use theseparameters to train the random forest model and predict the uniaxial compression strength and theYoung;s modulus of frozen fractured specimens with random number and geometry of ice-filled
fractures. The prediction results outperform the uniaxial compression strength and the Young;smodulus obtained from the Hoek-Brown failure criterion and the Ramamurthy criterion. Our study
indicates that machine learning method can be a reliable option to estimate the mechanical propertiesof complex fractured rock masses with randomly distributed fractures filled with various materials.

ARC13-A-0153-Coupled THMC Modeling on Acidizing Process in Fractured Carbonatite
Geothermal Reservoirs%+
Mr Haoran Xu Department of Civil Engineering, Tsinghua University, China
Dr Zhihong Zhao # Tsinghua University, China
Mr Feng Ma Institute of Hydrogeology and Environmental Geology, Chinese Academy of Geological Sciences,
China
Mr Guiling Wang Institute of Hydrogeology and Environmental Geology, Chinese Academy of Geological
Sciences, China
Mr Guihong Liu Department of Civil Engineering, Tsinghua University, China
Chemical stimulation, as a soft stimulation method, has been increasingly used in geothermal reservoirs
because of its low risk of induced seismicity. A nonreactive fluid is first injected to connect natural
fractures with hydraulic pressure, followed by injecting acid to etch fracture walls. The main aim of
this study is to further develop a fully coupled thermo-hydro-mechanical-chemical (THMC) modelingframework for chemical stimulation in carbonatite geothermal reservoirs containing a system ofintersecting fractures. A nonlinear constitutive models for rock fractures are included in the present
modeling framework. The developed modeling framework is verified using a case study of chemical
stimulation in the geothermal well, Xiongan New Area, China. The simulation results indicate that the
injection of high viscosity nonreactive fluid significantly increased the apertures of pre-existing
fractures and resulted in some tiny shear sliding of fractures within 10 meters from the wellbore. There
was no obvious fault slip induced, which was consistent with the results from microseismic monitoring.
Fractures with high initial aperture and strick parallel to the direction of maximum horizontal principal
stress are easier to be stimulated. The sensitivity analysis of acid concentration, injection rate,
perforation depth and direction are also carried out to provide an optimal solution for local acidizing
acid fracturing design.

Page | 17

ARC13-A-0154-Shear Behavior of Direct Shear Test for Natural Open Fracture and Infilled Fracture
Mr Tao LIN %#+ Tsinghua University, China
Dr Zhihong Zhao Tsinghua University, China
Filling materials in fracture significantly affect the mechanical behaviors of single rough rock fractures,
but the difference of natural open and infilled fracture during shear has not been entirely understoodand requires further investigation. In this study, direct shear tests were performed on the Beishannatural open and infilled granite fractures, respectively. The evolution of asperity damage during shear
was monitored using acoustic emission (AE) technique, and the asperity degradation zones anddamage volumes caused by shear were evaluated with the 3D blue light scanner. A laser diffraction
particle size analyser was used to examine the size distribution of sheared-off fragments. The results
showed that the shear strength of infilled granite fractures is larger than that of natural open fractures
under a lower normal stress because of the cohesive strength, which is different from most artificial
fractures with unconsolidated infilled materials. With the increase of the normal stress, the shear
strength of open fracture may exceed that of infilled fracture. The size of the sheared-off fragments inboth kinds of fractures under different normal stresses was found to follow a Weibull distribution but
particle size tended to be smaller in infilled fracture. Combining the proposed joint damage coefficientand the Weibull size distribution of the sheared-off fragments can approximately predict the potential
effects of sheared-off fragments on solute retardation coefficient for infilled fractures. The acoustic
emission ringing count and accumulated AE energy of two kinds of fractures follow the same law but
tend to be more drastic in open fracture, which complain the two main modes of asperity degradation
during shear, i.e., instantaneous failure of asperities occurring at the peak shear stress, and crushing of
the generated fragments with further shear displacement.

ARC13-A-0158-Intelligent Identification of Lithology and Adverse Geology in Tunnelling
Prof Zhenhao Xu %#+ Shandong University, China
Lithology variation zones and adverse geology often cause serious disasters in tunnelling. It isnecessary and important to develop non-destructive, in-situ, fast and intelligent means of identification
methods for lithology variation zones and adverse geology, so as to take corresponding
countermeasures in advance to reduce and prevent geological disasters. Here we report anddemonstrate some recent progress on deep learning-based methods for intelligent lithology andadverse geology identification in tunnelling. These methods are based on in-situ data collection (nonlab environment), deep learning and fusion analysis of images, element and mineral data of rocks. The
proposed methods were successfully applied in some tunnel engineering and can also be used insimilar surface geological surveying and subsurface mining and logging analysis in undergroundprojects.

ARC13-A-0159-A New Simulation Method for Grouting Process in Karst Fractures and Conduits:
the Sequential Flow and Solidification Method (sfs Method)
Mr Dongdong PAN %#+ Shandong University, China
Time-dependent viscosity characteristics of quick-setting slurry grouting lead to uneven distributionof viscosity in the slurry diffusion zone. At present, there still lacks reasonable and effective slurrywater interaction analysis method to reveal the diffusion behavior of quick-setting slurry in dynamic
water of karst fractures and conduits. A Sequential Flow and Solidification (SFS) method was proposed,
taking the spatial-temporal evolution of slurry viscosity into account. In addition, the validity andnecessity of the SFS method were verified. Based on the SFS method, the slurry diffusion process under
different flow velocities in a fracture was analyzed and the effects of flow velocities on the changes ofPage | 18

the grouting pressure, the counter-flow diffusion distance, and the down-flow diffusion behavior were
explored. The applicability and the feasibility of studying the slurry diffusion mechanism in a wideopen fracture on an engineering scale were determined. The SFS method is also applied to thenumerical investigation of dynamic grouting and blocking of flowing water in karst conduits. It
achieves the visualization of dynamic grouting in the conduit, and explores a reasonable and effective
method for dynamic grouting via the flow control technology. The outlet flow, the loss rate of slurry,
the distribution laws of velocity and pressure inside the conduit during plugging are furtherly
analyzed. In addition, the mechanism of flow control on dynamic grouting and plugging of the largeflow karst conduits is revealed. Moreover, the results were applied to the large-scale water inrush
control project of Hejing Limestone Mine, China. The SDS method can be used to simulate the dynamic
water grouting process, providing an improved method for the simulation of permeation andcompaction grouting.

ARC13-A-0162-A Coupled Thermo-mechanical Distinct Lattice Spring Model for Numerical
Modelling of Rock Thermal Fracturing
Mr Fuxin Rui %+ Tianjin University, China
Prof Gao-Feng Zhao # Tianjin University, China
Rock thermal fracturing is a key issue in the analysis of geothermal development, oil and coal seam gas
exploitation, strong electromagnetic wave assisted rock breakage, nuclear waste storage, crustal
evolution, etc. The effect of thermo-mechanical coupling is crucial to the propagation and evolution ofrock thermal fracturing. Distinct lattice spring model (DLSM) is a discrete element method that
discretizes matter into individual particles linked by springs, which has advantages in simulating the
dynamic failure and wave propagation in rocks. Nevertheless, it still lacks the ability to deal with multiphysics coupled problems. In this work, the concept of thermal pipe network is adopted in the DLSM
to duplicate the corresponding mechanical lattice so that the Fourier;s law can be solved at the pipe
level. In addition, the implementation of thermal pipe network in the DLSM is convenient to develop
the coupled thermo-mechanical constitutive model for rock failure and to derive the closed form
relationship between the macro and micro thermal parameters. The coupling relationship between thethermal and mechanical fields is addressed through the thermal expansion equation. Furthermore, thecoupled thermo-mechanical DLSM adopts a dual timeline coupling scheme that the mechanicaltimeline and thermal timeline can have different time scales, which enables the coupled model to both
deal with the transient and steady-state thermo-mechanical coupling problems. Finally, wedemonstrate a series of numerical examples to verify the applicability of the coupled thermomechanical DLSM.

Page | 19

SESSION TOPIC
T04 - SITE INVESTIGATION AND GEOLOGICAL MODEL
ARC13-A-0002-Determination of Fluvial Sand Layer Using CPTu Test Results for an Underground
Project in Singapore
Dr Jianping Sun %#+ CCCC-SJ PTE LTD, Singapore
Ms Lanting Wu China Communications Construction Company Limited (Singapore Branch), Singapore
Prof Siew Ann Tan Department of Civil and Environmental Engineering, National University of Singapore,
Singapore
A deep excavation was carried out at eastern part of Singapore which was 50m wide and 20m deep
based on the dimension of permanent structure. Steel pipe pile wall were proposed as the retaining
wall. Typical soil profile consists of 10m to 16m thick of reclaimed Fill, 7m to 32m thick of Kallang
Formation (Fluvial SAND and CLAY and Marine CLAY) and competent Old Alluvium of varying
weathering degree. There was potential risk of the ingress of water into excavation if the pipe pileinterlock was not grouted when fluvial sand was encountered. Therefore, the fluvial sand layer shallbe determined by soil investigation.The cone penetration test (CPTu) allows for a continuous soil
profiles and can collect independent readings in a single sounding. These readings, notably the cone
tip resistance (qc), sleeve friction (ft) and penetration pore water pressure (u2) are interpreted to givethe soil parameters used to assess subsurface stratigraphy. Since both the penetration resistance andsleeve resistance increase with depth due to the increase in effective overburden stress, the CPTu datarequires normalization for overburden stress. And normalized soil behavioral type (SBTn) chart
proposed by Robertson (1990) is commonly used. Another parameter, Soil Behavior Type Index Ic, isalso commonly used to represent the SBT zones in the SBTn chart. Furthermore, Robertson (2010)
proposed a simplified relationship between soil permeability and Soil Behavior Type Index, Ic and thisrelationship is used in this study.A series of cone penetration (CPTu) tests were carried out and Ic was
obtained based on normalized cone resistance and normalized friction ratio. Then the permeability wasestimated using the relationship between soil permeability and Ic, and the fluvial sand layer wasdetermined when the permeability is higher than 10-6 m/s. Finally, the interpretation of CPTu test
results was used in the design successfully.

ARC13-A-0025-A Review of Methods for Measuring Dynamic Characteristics of Fault Gouge
Dr Seong-Woo Moon %#+ Chungbuk National University, Korea, SouthProf Yong-Seok Seo Chungbuk National University, Korea, SouthThe methods for measuring P- and S-wave velocities were reviewed to obtain the dynamic
characteristics of fault gouge, calculated from the P- and S-wave velocities. Ultrasonic tests employ ahigher frequency source than in seismic surveys, which can reduce the accuracy of the measured data
via scattering and attenuation losses in porous fault gouge. Borehole surveys, such as down-hole, uphole, and cross-hole surveys, as well as suspension P-S (SPS) logging, measure the velocities of thesurrounding rocks, including fault gouge. The measured velocities can also be somewhat high or low
due to the borehole casing, which is installed to prevent the collapse of weak fault gouge in the borehole
wall. Seismic survey using direct waves and multichannel analysis of surface waves (MASW) surveys
were conducted on a trial basis to obtain the dynamic characteristics of fault gouge. The elastic wave
velocities from the seismic survey are reliable based on the first arrival calculations, and the S-wave
velocity was verified by identifying the polarity reversal. Meanwhile, a low S-wave velocity wasmeasured during the MASW survey. It is regarded as the reason why the analyzed surface wave wasproduced in a near-surface zone that contains different geological structures like faults, which lower
the S-wave velocity by inducing the reflection of ground roll.This research was supported by Basic

Page | 20

Science Research Program through the National Research Foundation of Korea (NRF) funded by the
Ministry of Education (2021R1I1A1A01040298).

ARC13-A-0089-Application of a Three-dimensional Quality Control System Based on Permeable
Fracture Information in a Dam Foundation Process
Mr Keisuke Kurihara %#+ Kajima Corporation, Japan
Ms Takako Miyoshi Kajima Corporation, JapanDr Kazuhiko Masumoto Kajima Corporation, Japan
In order to control the quality of the dam foundation processing, it is important to grasp the threedimensional permeability in the foundation rock mass. As grout slurry infiltrates through the fracturesin the rock mass, the quality should be evaluated by the permeable fracture information (its intensity,orientation and continuity) and construction data. However, since it requires a lot of time and labour,
it is necessary to quickly extract information on rock permeability from the data obtained in the
grouting process and to construct a system for easy evaluation and management. Focused on the imageof borehole wall during grouting, we developed a technique to automatically extract fracture
information and to quantitatively evaluate the three-dimensional continuity of fractures, using theimage analysis and AI technique. Furthermore, as this fracture information is integrated with theconstruction information, the quality of dam grouting could be evaluated as a three-dimensional
quality control system. This paper shows the results of application of this quality control system withthe actual constructing dam site.

Page | 21

SESSION TOPIC
T05 - SLOPE STABILITY AND LANDSLIDESARC13-A-0062-Glaciers, Sediments and Lineaments – Temporal, Spatial, Environmental and
Structural Constraints for the Evolution of the Dangkhar Landslide, Himachal Pradesh, India
Dr Markus Kaspar %#+ Graz University of Technology, Austria
Prof D. Scott Kieffer Graz University of Technology, Austria
With an estimated volume of approximately 15 to 20 km&sup3;, the Dangkhar Landslide located in theSpiti Valley, Himachal Pradesh, India, is one of the largest landslides on earth. Its initiation isgeochronologically constrained to have occurred during the late Pleistocene and may be related toglacial retreat following last local glacial maximum around 20,000 years ago. There is significant value
in understanding the causative factors contributing to such an enormous and rare event. On the basisof comprehensive field studies and laboratory investigations, it is concluded that erosional, structural,and depositional features within and surrounding the Dangkhar Landslide are critical forunderstanding landslide initiation and its long-term behavior.;The landslide developed as a block slide
along a synformal flexure, and through-cutting lateral valleys fulfill the kinematic conditions forcreating a massive removable block of earth. Deposits of weakly cemented and crudely bedded
carbonate breccias in the landslide;s toe region represent depositional activity during recession of themain valley glacier, and cross-cutting structural relationships involving ground ruptures (lineaments)
and rock glaciers in the head region record long-term, ongoing landslide deformations subsequent to
its initiation. Stable isotope signatures of samples indicate presence of freshwater associated with theformation of breccia deposits.;While many details concerning the timing and development of the
Dangkhar Landslide remain unknown, recent studies illuminate some very important aspects. The
glacial history of the Spiti Valley combined with structural kinematics are clearly important factors
concerning landslide development. Also important are constraints concerning the minimum age oflandslide initiation (20,000 years), and structural evidence documenting long-term ongoing slope
deformations.

ARC13-A-0041-Prediction of Landslide Potential Using Steady State Seepage in Unsaturated Soils
Karthikeyan MUTHUSAMY#+ Surbana Jurong Consultants Pte Ltd, Singapore
The stability of residual slopes is strongly influenced by climatic and hydrological changes such as
precipitation, infiltration, evaporation and transpiration processes. Landslides triggered by rainfall arecaused by the buildup of water pressure into the ground. Prediction of rainfall-induced landslides isproblematic as it needs a full understanding of flow processes and engineering behaviour of soil within
the unsaturated (or vadose) zone. It is generally accepted that the rapid rise of rainfall-induced porewater pressure is critical to the initiation of slope failures. The loss of matric suction and the advanceof the wetting front are controlled by the infiltration characteristics of the slope. An ability to model
this process is critical to an accurate assessment of slope stability problems. One way to evaluate theeffect of infiltration is to use an analytical formulation for the suction stress above the water table. On
the basis of this analytical formulation and the classical infinite slope stability analysis, Lu and Godt
(2008) proposed a first-order method for evaluating potentially unstable soil slopes subject to steadysurface infiltration. In this paper, a simple practical method based on a modified form of Lu and Godt
(2008) is proposed. The method evaluates an average antecedent rainfall intensity that could potentiallytrigger landslides above the water table. A series of parametric studies were conducted to study the
relative importance of soil properties, weathering characteristics, slope geometry, initial water tablelocation in inducing of landslides. Several case studies are presented to illustrate the potential
usefulness the proposed framework. The relationship between the predicted rainfall intensity versus
observed rainfall intensity for the landslide events shows the reasonable agreement, given the

Page | 22

significant simplifications involved, particularly the estimation of matric suction using steady state
infiltration and the vague definition of observed rainfall intensity. The analytical framework proposedin this paper is capable of assessing the likelihood and precipitation conditions that induce thetriggering mechanisms of landslides. This analytical framework could form part of a landslide warning
system or provide a quantitative basis for landslide risk assessment.

ARC13-A-0067-Mechanism of Resurrection of Ancient Landslides within the Xiaonangou
Watershed of Yan'an CityDr GU QI %#+ Northwest University, China
Yan'an, Shaanxi Province, is located in the middle reaches of the Yellow River, and its uniquegeomorphology and fragile ecological environment make landslide disasters frequent. Due to theshortage of land resources in the city, people are expanding urban space with a large number ofdevelopment watersheds, inducing the resurrection of many ancient landslides. The resurrection ofancient landslides poses a threat to soil and water conservation, ecological environment, engineering
construction, human and property safety, so it is extremely important to study the resurrection
mechanism and propose green management measures. In this paper, we use geological survey,
geological mapping and geotechnical investigation to obtain the ancient landslide boundary,stratigraphic lithology and watershed DEM. On this basis, we find that the moisture and soil shear
strength in the ancient landslide body increase with depth, and there is a certain degree of decay lawof soil shear strength near the sliding surface. Through the processing of remote sensing image data ofvegetation in the study area and long-term subsidence and rainfall monitoring on site, it is found thatrainfall affects the degree of vegetation cover, and different degrees of vegetation cover make theresurrection of paleolandslides different. Based on the resurrection factors of ancient landslides in thewatershed and the results of indoor experiments, the author proposes the resurrection mechanism ofancient landslides in the watershed. This paper can provide an insight to deal with the resurrection ofancient landslides with a watershed as a starting point.

ARC13-A-0085-Retrogressive Landslide: a Bitter Lesson from Cimanggung Landslide of
Sumedang, Indonesia
Mr Imam Sadisun Institut Teknologi Bandung, Indonesia
Mr Indra Andra Dinata %#+ Institut Teknologi Bandung, Indonesia
Mr Rendy Dwi Kartika Institut Teknologi Bandung, Indonesia
Mr Astyka Pamumpuni Institut Teknologi Bandung, Indonesia
Mr Alditama Prihadi Prihaditama Ltd. Co., Indonesia
The Cimanggung landslide occurred on Saturday, January 9, 2021 just after very heavy rainfall. The
landslide was a complex landslide showing a change from slide to flow mechanism of debris. It wasevidenced that the landslide was not a single event, but at least four landslides occurred as retrogressive
developments of the crown. The first landslide with a semi-rotational type took place at 15.30 local timeand claimed 8 lives. The second landslide occurred retrogressively at 19:15 and was followed by adebris flow which resulted in the death toll of 32 lives. It is estimated that this second landslide is muchlarger than the first, from about 20 m crowns with a length of up to 45 m, to 50 m crowns with a debris
outflow reaching of up to 120 m. In this case, the third and fourth landslides tended to occur locally inthe second landslide scarp.The landslide location has several layers of rock and soil. Those rock andsoil layers are lightly weathered breccia tuffs, strong weathered breccia tuffs, residual soils, and landfill.
The drainage in upper houses looks ineffective after the landslide. The water flowing through thedrainage seeps into the cracks that form behind the landslide crown. Landslide crown is still actively
moving backwards (heading east) because the slope conditions are still unstable due to the condition

Page | 23

of the water and constituent materials. The retrogressive landslides which followed by debris flow will
be modeled to determine the run-out distribution. The results of this modeling will be used as areference for the emergency response team to secure similar landslides which followed by debris flowat other locations.

ARC13-A-0086-Landslide Science of the Himalaya in the Consequences of Deep-seated Slope
Deformations
Dr Ranjan Kumar Dahal %#+ Central Department of Geology, Tribhuvan University, Nepal
Dr manita Timilsina Geotech Solutions International, Nepal
Prof Shuichi Hasegawa Faculty of Engineering and Design, Kagawa University, Japan
Himalaya Mountains need a comprehensive evaluation of geomorphological evolution of slope tounderstand engineering geological study of soil and rock in slopes. In the Himalayan region, role
played by the deep-seated slope deformations (DGSDs) for the evolution of relief and hillock arefundamental issues of engineering geomorphology and they need to be pointed out in different
geological and geomorphological conditions of the Himalaya.Being a geologically young and active
Himalayan belt, the Nepal Himalaya is having issues of deep-seated slope deformations. Deep-seatedslope deformations and their related large-scale landslides are complex phenomena taking placethrough a wide variety of mechanisms whose genesis and evolution are controlled by several factors,
among which structure, relief, and tectonic and seismic activities have a particular importance. The
deep-seated slope deformations have typical morphological elements which help to recognize them in
topographical maps and satellite images along with field data. The surface extension of deformation is
generally more than 1 square km with thickness of deformed mass ranges around several tens tohundreds of square km. These deformations related large-scale landslides lack a continuous slip orshear surface delimiting the deformed mass. The rate of movement of deformation is slow, happening
in past geologic times with long periods of inactivity. But sometimes they might be active after aconsequence of earthquakes or extreme rainfall or human interventions. The deformed slopes are often
involved in many shallow-seated landslides and have less drainage density.Observations of projectsites in the Himalaya have been suggesting that they are highly affected by existing deep-seated slope
deformations related large-scale landslides. In Himalaya, site investigations for tunnels and roads do
not follow engineering geomorphological study and they are limited to rock mass characterization
along with geological and engineering geological mapping only. Engineering geomorphologicalevaluation of tunneling site before the project commencement can help to reduce project cost andunnecessary delay of the projects using a blaming phrase: &ldquo;the Geological
Issues&rdquo;. ;Therefore, this paper will highlight the importance of engineering geomorphologicalstudy emphasizing DGSDs in the Himalayan region with few examples.

ARC13-A-0110-Landslide Hazard Mapping Using GIS and GANs at Central Parts of Badakhshan
Province, Afghanistan
Mr Bashir Ahmad Jalali %+ Graduate school of International Resource Sciences, Akita University, JapanMr Taeyoo Na Graduate school of International Resource Sciences, Akita University, JapanMr Hirokazu Furuki Nippon Koei Co, Japan
Prof Itaru Kitahara Center for Computational Sciences, University of Tsukuba, Japan
Dr Youhei Kawamura # Akita University, Japan
Landslide awareness especially in areas prone to this naturally occurring geological hazard is of utmost
importance. There are several traditional methods that have been employed with successes and failures
being part of their nature with a goal to understand and guard against them. These methods are
however deemed rather haphazard in this digital world where structure, relationship between

Page | 24

variables, and tractability, are of extreme importance. With central parts of Badakhshan Province,
Eastern-North Afghanistan being the focus of our research, this paper attempts to integrate Geographic
Information System (GIS) and Generative Adversarial Networks (GANs) in the mapping of landslide
hazards within this area. To achieve this, we attained datasets from the Ministry of mines andpetroleum of Afghanistan; which can be generalized as landslide preparedness of the populations
within and around our study area, and landslide trigger factors. Having accumulated this data, we
employed a GAN whose duty was to automatically discover and learn the patterns in input data insuch a way that the model can be used to generate or output new examples that plausibly could havebeen drawn from the original dataset, thereby allowing one to the assess the occurrence of a fakelandslide as though it could or had occurred; One would call this predicting the future and preparing
for it before it comes. Outputs from the GAN are then exported into the GIS map in conjunction withthe actual data to find the best mitigating techniques. From the results we attained, we were able tolocate unstable hazard-prone areas, this will potentially aid in environmental regeneration programs
whose goal is to initiate suitable and relatively more practical mitigation measures.

ARC13-A-0128-Developing Landslide Susceptibility Map Using Weight of Evidence Method: aCase Study from the Northern Stretch of Arun River Watershed, Arun Tectonic Window, East
Nepal
Mr Harish Dangi % NEA Engineering Company Limited, Nepal
Mr Diwakar K C #+ University of Toledo, United States
Mr Sudarshon Sapkota NEA Engineering Company Limited, Nepal
Mr Saroj Niraula Nepal Electricity Authority, Nepal
Mr Pushkar Bhandary NEA Engineering Company Limited, Nepal
Mr Keshav Shrestha NEA Engineering Company Limited, Nepal
Mr Trilok Chandra Bhatta Vidyut Utpadan Company Limited, Nepal
Dr Liang-Bo Hu Department of Civil and Environmental Engineering, University of Toledo, United States
The Arun River, a transboundary perennial river flows from China to Nepal along with the Arun
tectonic window, East Nepal. The Arun River watershed experiences significant slope instability as
landslides occur frequently every year. The present study aims to prepare a landslide susceptibility
map of the northern stretch of the Arun River watershed. The study area lies on the northern stretch of
the Arun River watershed where both lesser Himalayan and higher Himalayan rock units are located.
The GIS-based Weight of Evidence method is adopted in this research to identify the landslide
susceptibility. Field investigation of the study area concludes that the combination of the following fiveparameters including topography, hydrology, geology, land use pattern, and intense rainfall withseasonal snowfall, play a crucial role in the landslide events in this region. A landslide susceptibility
map is developed incorporating the consideration of the slope characteristics (slope angle, slope aspect,and slope shape), as well as the stream proximity, the stream power index, the lithology, and the landuse practices. The results show that 83% of the past landslides lie within the high to very highsusceptibility zone in the map. The present study demonstrates that the development of the landslide
susceptibility map could have a significant impact on the landslide hazard risk mitigation and land use
management in this region.

Page | 25

ARC13-A-0135-Theoretical and Numerical Simulation Investigations on Rock Block Seismic
Movements in the Three-dimensional SpaceMr Xinyang Lv %+ Southwest Petroleum University, China
Prof Youjun Ning # Southwest Petroleum University, China
Seismic sliding of rock masses is a serious earthquake hazard. Under the action of earthquake loads,
rock blocks may move longitudinally downwards inclined surfaces, while the lateral movement also
could be significant. In the present work, the seismic movements of rock blocks in the threedimensional space is studied. On the one hand, theoretical solutions of a single block moving on an
incline under seismic loads is derived. On the other hand, the seismic loading function is added to thethree-dimensional discontinuous deformation analysis (3D DDA) program that was enhanced by theContact Theory for block contact detection, and 3D DDA simulation of seismic movements of rockblocks on inclines is carried out. It shows that the theoretical and numerical results of the acceleration,
velocity and displacement in the longitudinal and lateral directions of a single block on an incline agree
well under various seismic loads parameters (amplitude, phase and frequency) and incline parameters(slope and friction coefficient). Influences of the seismic loads in the three directions (one in verticaland two in horizontal) on the longitudinal and lateral movements of a single block and multiple rockblocks are carefully studied through the theoretical and numerical analysis. This work builds goodbasis for the further 3D DDA simulation of earthquake-induced rock mass movements and the further
investigations of seismic sliding hazard.

Page | 26

SESSION TOPIC
T06 - GEOHAZARD ENGINEERING AND RISK ASSESSMENT

ARC13-A-0026-Probabilistic Landslide Run-out Hazard Evaluation for Quantitative Risk
Assessment%#+
Dr PENG ZENG
Chengdu University of Technology, China
Mr Xiaoping Sun State Key Laboratory of Geohazard Prevention and Geoenvironment Protection, China
Mr Qiang Xu State Key Laboratory of Geohazard Prevention and Geoenvironment Protection, China
Mr Tianbin Li State Key Laboratory of Geohazard Prevention and Geoenvironment Protection, China
Quantitative risk assessment of landslides requires the probabilistic evaluation of spatial impact of runout processes. To that end, it is necessary to estimate landslide run-out intensities (e.g., extension,
deposition height, velocities) using probability methods, i.e., probabilistic landslide run-out hazard
evaluation. In this paper, a general framework is presented to estimate three-dimensional spatial
impact probability for landslide run-out. In the presented framework, a continuum mechanics conceptbased dynamic numerical model namely Massflow, is used to conduct run-out analyses. However, theproper selection of model input parameters still remains the biggest challenge in the run-out modelingbecause they are tied to large uncertainties. To systematically quantify those uncertainties, model input
parameters are defined as random variables subject to reasonable probability distributions (i.e., priordistributions), and their distributions are efficiently improved through Bayesian inference withmultiple-observations (observed deposition heights at different points in the past landslide
accumulation area). Then the calibrated distributions (i.e., posterior distributions) can be used as an
input with reliability methods to estimate run-out exceedance probability (i.e., spatial impact
probability of landslide run-out) of the potential landslide similar to the past landslide, and to produce
run-out hazard maps. Kriging-based surrogate models are used to improve the computational
efficiency. To illustrate the performance of the proposed framework, we apply it to two successive
sliding of landslide CJ#8, which is located in the Heifangtai, Gansu, China. The computed results areused to produce probabilistic run-out hazard maps of maximum run-out intensities exceeding various
run-out height thresholds (i.e., 0 m and 1.5 m) and various run-out velocity thresholds (i.e., 1.5 m/s and3 m/s). The maps can be visualized in a GIS platform, and superimposed on top of the landslide
numerical elevation model or satellite image map, making it easy for decision makers to know the areasthat may be affected by the landslide. In addition, the computed results can be used for probabilistic
vulnerability evaluation in the quantitative risk assessment. Probabilistic risk analyses allow a
costbenefit analysis-based prioritization of mitigation strategies and data support for land planningand management.

ARC13-A-0043-The Analysis of Three-dimensional Surface Deformation in Heifangtai Platform
Using Ps-insar Technology
Mr Chenxing Wang %#+ Chang'an University, China
Prof Tonglu Li Chang'an University, China
The serious surface subsidence and deformation has occurred due to the long-term agricultural
irrigation in the Heifangtai area, as a typical loess tableland, and has induced many loess landslides.
However, limited by the observation methods, the research on the three-dimensional deformation
characteristics of this area was limited. The surface deformation in the Heifangtai Platform was taken
as the research object in this study. The principle of obtaining three-dimensional surface deformation
based on PS-InSAR technology was introduced. Besides, based on the deformation data of sentinel-1A
satellite in different orbits, the characteristics of three-dimensional surface deformation in the
Heifangtai area from 2014 to 2017 were analyzed, and its development trend was predicted. The results

Page | 27

show that the vertical deformation in the middle of the tableland is large, especially in the villages andnearby villages, and the average deformation rate is -20～-6 mm/y. Meanwhile, the hazardous area oflandslide along the tableland has large vertical deformation. The deformation results of the 9 regions
selected show that the east-west deformation in the whole tableland is large, and the averagedeformation rate is more than 20 mm/y, which is much higher than that in the north-south direction(e.g. -5～5 mm/y). Therefore, there are uneven settlements in the study area. Besides, the surface
subsidence in the study area still maintains a slow and accelerated development stage in the short term.
This study provides a reference and guidance for the study of the multi-dimensional deformation
characteristics of the surface in the prone area of loess landslide induced by irrigation.

ARC13-A-0084-Debris Flow Disaster Preparedness: Learning from 22 February 2018 Pasir Panjang
Debris Flow Case
Mr Imam Sadisun Institut Teknologi Bandung, Indonesia
Mr Indra Andra Dinata %#+ Institut Teknologi Bandung, Indonesia
Mr Rendy Dwi Kartika Institut Teknologi Bandung, Indonesia
Landslide followed by debris flow on February 22, 2018 has caused physical and psychological damage
to Pasir Panjang village which hard to forget. Residents still frightened by a similar potential disasterin their village. A series of efforts were made to increase preparedness for similar potential disasters.
These efforts include modeling the debris flow on 22 February 2018 run-out distribution, carrying out
the boundaries of its hazard zones, transfer knowledge on debris flow emergency response. This seriesof efforts is Institut Teknologi Bandung community service program to apply knowledge in disastermitigation activities. The results of debris flow numerical simulation model on February 22, 2018 wereable to show the distribution of debris material. The model has 0.3 material concentration, 275 thousand
m3 debris volume, 26 km/hour flow rate maximum speed, and flows as far as 2.3 km. Based on the
results model, the debris flow hazard zones can be determined. The information is used as an analogy
for hazard zone in several locations that has debris flow potential in Pasir Panjang Village

ARC13-A-0097-Spatial-temporal Evolution Characteristics of Land Subsidence and Ground Fissure
Using SBAS-InSAR: a Case Study of Yuhua Village in Xi’an City
Dr Jiewei Zhan %#+ Chang’an University, China
Ms Yuemin Sun College of Geological Engineering and Geomatics, Chang’an University, China
Prof Quanzhong Lu College of Geological Engineering and Geomatics, Chang’an University, China
Since the late 1950s, Xi'an City has suffered from serious land subsidence and ground fissures, which
seriously restricted the urban construction and development planning of Xi'an City. In this paper,
Yuhua Village, one of the typical land subsidence areas in Xi'an City, is taken as the research area. Basedon the SBAS-InSAR technique, three kinds of satellite data (ERS, Envisat, Sentinel-1a) covering thestudy area from 1992 to 2020 are used. Combined with the drilling data, the history and current
situation of urban underground water exploitation and development, this paper analyzes the temporaland spatial evolution characteristics of land subsidence and ground fissures around Yuhua Village, anddiscusses the genetic mechanism of land subsidence and ground fissures. The main results are as
follows: annual deformation rate maps in Yuhua Village and surrounding area from 1992 to 2020 are
obtained, and the subsidence center changes from the electronic city (90 mm/a) in the 1990s to the
Yuhua Village (50 mm/a). There is a correlation between land subsidence and ground fissures in spacetime distribution, and the ground fissures are exposed in the north edge of the ground subsidence
trough, and expand according to the development of the ground subsidence trough. The subsidence
center of Yuhua Village is still expanding, and the f4 ground fissure may extend westward. The
development of ground subsidence and ground fissure around Yuhua Village is affected by the

Page | 28

exploitation of underground confined aquifer and human construction activities. The above results canprovide certain reference and theoretical support for urban land development and disaster prevention
affected by land subsidence and ground fissures.

ARC13-A-0121-The Dynamic Response Characteristics of Sites with Earth Fissures
Mr Jiang Chang %#+ Chang`an University, China
Mr Yahong Deng Chang`an University, China
Mr Huangdong Mu Xi`an University of Technology, China
As a widespread geological hazard, the disaster development process of earth fissures is irreversible
and difficult to control, which seriously affects the construction and safe operation of engineering
facilities. However, few clear conclusions and special regulations have been given regarding theinfluence of earth fissures on the dynamic response characteristics of a site and earthquake prevention
and disaster reduction measures. With the aim of providing previously lacking advice regarding
earthquake fortification in proximity to fissures, systematicmicrotremors testing were conducted.The
typical earthfissures in the Fenwei Basin were taken as as the research objectand more than 40
microtremor survey lines were laid.In order to reveal the dynamic response of microtremors fromseveral aspects, four methods, including the Fourier spectrum, the horizontal-to-vertical spectral ratio(HVSR), the response acceleration, and the Arias intensity, were employed.Finally, the dynamic
response characteristics, influencing factors, ground motion amplification effect, influence range,engineering protection distance and seismic fortification criteria of earthfissure sites are revealed andproposed. The results show that a greater dynamic response can be found near the earth fissure. The
amplification effect decreases and eventually disappears with increasing distance from the fissure. A
series of amplification attenuation curves were calculated, the empirical equations of various sites were
determined and seismic fortification distance were estimated. Research on the dynamic response
amplification effect of earthfissure sites will alsoprovide technical support to disaster prevention andmitigationof similar sites.

ARC13-A-0123-Is the Factor of Safety Reliable for Assessing the Stability of Fluid-overpressurizedRock Fractures?
Dr Mingdong Wei %#+ Nanyang Technological University, Singapore
Prof Wei Wu Nanyang Technological University, Singapore
Fluid pressurization in rock fractures under extreme conditions, such as reservoir impoundment andhydraulic fracturing, may accelerate the instability of fractured rock masses. Fluid pressure can reduce
the effective normal stress on rock fractures and cause the degradation of the shear strength, resulting
in destructive geohazards. Recent evidences show that the factor of safety (FOS) defined by the
traditional methods may not predict the stability of rock masses appropriately. In our study, laboratory
experiments, numerical simulations, and theoretical derivation are conducted to investigate the effectof fluid pressure distribution on the FOS assessment. We find that the Mohr-Coulomb failure criterion
is inapplicable to predicting the instability of low-permeability fractures under significant fluidpressure gradients, and the FOS evaluated based on the failure criterion can be much higher than 1.
The more considerable the fluid pressure gradient, the higher the FOS at fracture failure. Thus, asignificant fluid pressure gradient may cause the premature failure of a rock fracture. Our analysis also
indicates that the upper bound of the FOS at fracture failure under a non-linear fluid pressure gradientdepends on the initial FOS of the fracture without fluid pressurization. The findings help advance theunderstanding of rock mass instability due to fluid pressurization and the safety control of rockengineering projects under extreme conditions.

Page | 29

ARC13-A-0146-Geohazards and Human Settlements: Lessons Learned from Multiple Relocation
Events in Badong, China – Engineering Geologist’s Perspective
Prof Wenping Gong %#+ China University of Geosciences (Wuhan), China
Prof C. Hsein Juang Clemson University, United States
Prof Janusz Wasowski National Research Council, Italy
Mountainous regions are inherently susceptible to geohazards, such as landslides and debris flows,with the threat of natural disasters compounded by human activities (mainly settlements). Lessons
learned from past events that involved the interactions between human activities and geohazards arehelpful for future site selections of human settlements in mountainous regions. To this end, the events
associated with county seat relocations in Badong, a typical county in the Three Gorges Reservoir
region, China, are studied from an engineering geologist’s perspective. Over its history, the county seat
was relocated multiple times, with the first relocation traced back to the Song dynasty (960-1279 A.D.)
and the last two relocations linked to the Three Gorges Dam project. By studying geohazards and theirinteractions with human activities in these county-seat relocations, and through the reconstruction ofthese events, we secure insights into decision-making for these events. As part of the reconstruction ofthese relocation events, we analyze a giant pre-historic landslide, whose discovery ultimately prompted
the third relocation. Using the case history of this landslide, we also discuss and emphasize theimportance of proactive monitoring of geohazards for disaster resilience enhancement, recognizing that
our knowledge of nature is vastly incomplete.

ARC13-A-0148-Debris Flow Management along the National Highway in Korea
Dr Seung-Hyun KIM %#+ Korea Institute of Civil Engineering & Building Technology, Korea, SouthDr Byung-Suk PARK Korea Institute of Civil Engineering & Building Technology, Korea, SouthMr Yong-Hoon WOO Korea Institute of Civil Engineering & Building Technology , Korea, SouthIn Korea, there are about 70% of mountainous areas and most landslides are rock failure. Nevertheless,debris flow sometimes occurs due to heavy rain. Debris flow occurs in the blink of an eye, the damage
area is very large, so it is highly likely to cause casualties, so systematic management is needed. The
management of debris flow was strengthened nationwide in the wake of the landslide at Umyeonsan
Mountain in Seoul, but CSMS(Cut Slope Management System project by Ministry of Land,
Infrastructure &amp; Transport(MOLIT)) did not manage debris flow before 2013. The mountainous
area where debris flow occur was under the jurisdiction of the Korea Forest Service(KFS), and roadlandslides were said to have nothing to do with debris flow. The need for management has emerged as
torrential rains caused by global warming have increased the number of debris flow invading roads. In
the management of roadside debris flow, there was initially confusion in the management of debris
flow and in the setting of survey items. We made several key tasks to solve this issue ; To prepare items
and checklists for debris flow field surveys, prioritization of investigation considering risk and damagelevels of debris flow, classification of countermeasures to prevent debris flow damage &amp;
establishment of a cooperative system between MOLIT and KFS. KFS already operates geohazard map
for damage prediction of debris flow and geohazard map for Integration Debris flow, taking into
account topography, geology, and population. But this map itself does not take into account roads into
account. Nevertheless, we think this map can play an important role in extracting debris flow risk areas
along national highway. In 2021, we're going to find and list the overlapping parts of the existing debris
flow hazard map and roads. We are going to conduct a joint investigation on the debris flow points
where the risk is high and make a countermeasure. Of course, it will be possible to operate the debris
flow checklist and investigation priority techniques.

Page | 30

SESSION TOPIC
T07 - SENSOR TECHNOLOGY AND DATA ANALYTICS IN ENGINEERINGGEOLOGY
ARC13-A-0009-Study on Soft Subgrade Settlement Via Optical-fiber Bidirectional Zigzag Based on
Dofsm
Dr Chaoqun Wei %+ China University of Geosciences, China
Prof Qinglu Deng # China University of Geosciences, China
Mr Kangqing Deng China University of Geosciences, China
Mr Mengyao Yan China University of Geosciences, China
Mr Weiwei Su China University of Geosciences, China
Soft subgrade settlement has always been a prime factor affecting construction quality in coastal areasof China and other countries. Corresponding settlement and deformation monitoring are very essential,
as they can carry out process monitoring for soft subgrade and nearby engineering. Conventional pointtype monitoring instruments have the advantages of simple operation, reliable precision, andconvenient data processing. However, the point-type sensors are only selectively installed in somelocations, resulting in missing inspections, to a certain extent. Recently, distributed optical fiber sensing
monitoring (DOFSM) technology has been studied deeply and applied consistently. Its full distribution,
anti-electromagnetic interference, corrosion resistance, high precision, and other characteristics canaccurately realize laboratory studies and engineering applications. This study designs a novel fiber
layout mode with a bidirectional zigzag shape based on DOFSM to monitor the settlement and analyze
the results. This work theoretically analyzes the feasibility of settlement and deformation monitoringof soft subgrade using optical fibers laid in a bidirectional zigzag. Then, the optical fibers data are
analyzed via the designed bidirectional zigzag layout in the field monitoring study, and traditional
point-type monitoring results are compared. The results show that the novel fiber layout in abidirectional zigzag can theoretically carry out the conversion calculation from strain value tosettlement value in monitoring soft subgrade. The settlement values of the monitored area can beobtained through the related calculation in the field monitoring using a theoretical formula. Compared
to traditional monitoring results, DOFSM results using a bidirectional zigzag layout can obtain more
on-site data, and the results are more accurate and more in line with the actual situation. Moreover, thethree-dimensional camber graphics of soft subgrade with optical fibers data are obtained to analyze thechanging trends. The results reflect the settlement and deformation trend of soft subgrade during themonitoring period more intuitively. DOFSM, in the form of the bidirectional zigzag layout, can better
implement the settlement and deformation monitoring of the subgrade, providing a reference forfurther study.

ARC13-A-0044-Application Of UAV-based Photogrammetry To Extract Fracture Planes Of Dam
Foundation Rock Mass In Japan
Ms Takako Miyoshi %#+ Kajima Corporation, JapanDr Hayato Tobe Kajima Corporation, JapanMr Yasuhiro Yokota Kajima Corporation, JapanMr Kensuke Date Kajima Corporation, JapanDr Mohd Ismail School of Civil Engineering, Universiti Sains Malaysia, Malaysia
The key roles of dam foundation rock mass are to provide sufficient strength to support dam
embankment, and to resist to leakage of water. When considering resistance to leakage of water, it isimportant to understand the fluid flow within the rock mass. For example, in fractured rock mass, fluid
tends to flow through permeable fractures. Therefore, in such case, understanding fracture properties

Page | 31

(size, intensity, and orientation) of dam foundation rock mass is critical in support of dam foundation
design. Fracture data are collected through geological surveys including core logging and surface
mapping. Although surface mapping such as window mapping allows collection of two-dimensional(2-D) data of fractures, surface mapping typically requires field geologists to manually record
geological information and tends to be time-consuming. In recent decade, with the advancements inremote sensing techniques and computer efficiency, there are new technologies to acquire digital fielddata remotely at shorter time. One example is the application of UAV (Unmanned Aerial Vehicle) based
photogrammetry combined with SfM (Structure from Motion) techniques in acquisition of fracture
data. Although this technique has been applied to various rock engineering applications, theapplication to flat rock surface such as dam foundation rock mass has not been examined. This paper
studies the application of UAV-based photogrammetry to extract fracture planes from flat rock surface
using a case study of dam foundation rock mass in Japan and examines the results by comparing
fracture properties. The comparison showed strong agreement between fracture orientations anddistributions obtained through UAV-based photogrammetry and window mapping, which implied
applicability of the method to dam foundation rock mass.

Page | 32

SESSION TOPIC
T08 - ENERGY EXTRACTION AND STORAGE
ARC13-A-0017-Physical-mechanical and Drillability Characteristics of Ziliujing Conglomerate
Formation in Western Sichuan Basin of China
Mr Tianshou Ma %#+ Southwest Petroleum University, China
Mr Yun Zhang Southwest Petroleum University, China
Mr Nian Peng Southwest Petroleum University, China
Mr Gongsheng Zhu Southwest Petroleum University, China
Mr Qiang Su PetroChina Southwest Oil & Gas Field Company, China
The conglomerate rock is usually featured by strong heterogeneity, high abrasiveness, and poor
drillability due to its complex composition and texture, which brought a huge challenge for drilling
efficiency. In order to guide the drill bit selection and high-efficiency drilling, the physical, mechanical,
and drillability characteristics were investigated for conglomerate rock that collected from the lower
Jurassic Ziliujing formation in the Western Sichuan Basin of China. The mineral composition, SEM
micro-structure, P- and S-wave velocities, uniaxial and triaxial compressive testing, drillability,
abrasiveness were systematically tested and analyzed. The mechanical properties and anti-drilling
ability of Ziliujing formation were proposed for a typical deep well of S-07, and the distribution
characteristics were analyzed. The results indicated that the Ziliujing rock is rich-in quartz and clay
minerals, due to the co-existing of strong quartz gravel and weak argillaceous cement, the Ziliujing
rock shows strong heterogeneity. The relationships are roughly linear among UCS, drillability, andgrinding weight loss with P-wave velocity. The Young’s modulus, UCS, internal friction angle,
drillability, and abrasiveness meet the Weibull distribution pattern, while only the Poisson’s ratio meets
the Kernel Smooth distribution pattern. The Ziliujing formation has the Young’s modulus of
38.61&plusmn;17.08GPa,the
Poisson’s
ratioof
0.327&plusmn;0.006,
the
UCS
of
93.02&plusmn;40.89MPa, the internal friction angle of 49.21&plusmn;11.00&deg;, the drillability of
8.04&plusmn;1.54, and the abrasiveness grade of 4.32&plusmn;1.94. The mechanical properties andanti-drilling ability of logging interpretation are in good agreement with the experimental data. Thus,
the Ziliujing formation is a kind of hard rock with strong heterogeneity, high strength, poor drillability,
and medium abrasiveness. The physical-mechanical and drillability results can be utilized to guide thedrill bit selection and high-efficiency drilling.

Page | 33

SESSION TOPIC
T09 - HYDROGEOLOGY AND GEOCHEMISTRY
ARC13-A-0013-Identification Of Geochemical Anomalies And Target Area Delineation In The
Lüliangshan Area, North Qaidam, Western China: Combined Log-ratio Approach And Robust
Factor Analysis
Dr Yueming Yin %#+ China University of Geosciences, Wuhan, China
Prof Qinglu Deng China University of Geosciences, Wuhan, China
In recent years, it was found that identification of weak geochemical anomalies in thick overburden
areas is of great economic significance, such as areas thick covered with vegetation, weathering layer
or desert. According logarithmic transformation can avoid the closure effect of composite data,
logarithmic ratio transformation and robust component analysis (CODA FA) were used to identify the
combination of mineralization elements. In L&uuml;liangshan research area, North Qaidam, based on
stream sediment sampling geochemical data, it was determined that Cu, Zn and Co have highcorrelation, and the geochemical mineralization anomalies of single geochemical element Cu, Zn, Co
and combined element Cu+Zn+Co were identified by traditional geochemical statistical method andMultifractal singularity analysis (S-A), and potential exploration targets were delineated in this sutdy.
It was found that S-A method can not only accurately delineate more obvious anomalies but also more
prominent weak anomalies than the abnormal lower limit mean &plusmn; 2 standard deviation (mean&plusmn; 2STD) of statistical method. And then, the analysis results obtained by statistical method andS-A method were compared with field geological exploration, several copper ore bodies and massive
copper mineralization have been discovered in the designated anomalous area that targeted by
combinatorial elements anomaly map. Therefore, the target area had considerable accuracy andeconomic value, it can point out the direction for future exploration of copper deposits in this area. And
it can be concluded that the combination of log-ratio approach, Robust compositional factor analysis
and Multifractal singularity analysis is an effective method for identifying geochemical anomalies.

Page | 34

SESSION TOPIC
S01 - NUMERICAL AND EXPERIMENTAL ADVANCES IN MULTISCALE
FAILURE ANALYSIS IN ENGINEERING GEOLOGY
ARC13-A-0019-Seepage Characteristics of Chemical Grout Flow in Porous Sandstone with a
Fracture Under Different Temperature Conditions: an Nmr Based Experimental Investigation
Mr Yuan Zhou %#+ Wuhan University, China
In this study, the low-field nuclear magnetic resonance (NMR) testing technique was adopted toexperimentally investigate the seepage processes of chemical grout flow in fractured rock mass undervarious confining pressures and temperatures. The variations in the NMR parameters, including thetested porosity, transverse relaxation time (T2) distribution and T2 peak area were quantitatively
analyzed to study the seepage characteristics under different grouting conditions. The changes in the
grout viscosity against the temperatures were studied. Then the effects of injection pressures andtemperatures on the seepage characteristics of the porous sandstone with a single fracture underconstant confining pressure of 20 MPa were systematically investigated. The results indicate that theviscosity of the grout shows obvious time-dependency characteristics and is strongly affected by thetemperatures. The flow pattern of the grout is greatly dependent to the injection pressure, whereas it isless affected by the temperature. The permeability of the porous sandstone shows an increase trend as
the injection pressure increases and the temperature decreases.

ARC13-A-0020-Numerical Investigation of Coupled Effects of Temperature and Confining
Pressure on Rock Mechanical Properties in Fractured Rock Mass Using the Thermal-stressaperture Coupled Model
Ms Mengyi Li %#+ Wuhan University, China
Dr Zhijun Wu Wuhan University, China
The mechanical performance of rock mass subjected to the coupled influences of the elevatedtemperature and in situ stresses has always been a hot topic in underground rock engineering projects.
In this study, a thermal-stress-aperture coupled model was first developed and then incorporated into
the particle flow code for the coupled thermo-mechanical analyses in fractured rock mass. Withthorough considerations of the aperture-dependent thermal and meso-mechanical parameters for thefractured rock, the model performed more realistic thermo-elastic responses of fractured rock to thetemperatures and confining pressures. Comparative studies between the numerical simulations andprevious experimental results indicated that the proposed model was suitable for modelling thethermo-mechanical behaviors of fractured rock. Then, a series of numerical compression simulations
with heating temperatures of 20-600oC and confining pressures of 0-20 MPa were conducted tocomprehensively explore the interplay of the temperature and confining pressure on mechanicalproperties of fractured rock specimens. Finally, the mechanisms that affect the rock thermo-mechanicalproperties were further revealed. The results indicated that the compressive strength and elastic
modulus increase with the increase in confining pressure for each temperature scenario. The thermal
strengthening behavior of rock extrapolated to about 400oC takes place in confined compression tests,
and is more pronounced at higher confining pressures. The evolutions of thermal properties, microcracks and meso-structure are the most decisive factors that could induce the variations of rockproperties under the coupled temperature and confining pressure treatment. For analyzing themechanisms behind strengthening and weakening contribution to rock properties, the positive effectof average fracture aperture variation, the dual effects of increased porosity and thermal-induced
micro-cracks, and the negative effect of stress-induced micro-cracks should be comprehensively
considered.

Page | 35

ARC13-A-0055-Numerical Modeling Compaction and Dilation Induced Permeability Changes in a
Laumontite-rich Tight Rock in Laboratory and Field Scales
Mr Zubair Akhter %#+ Concordia University, Montreal, Quebec, Canada
Mr Biao Li Department of Building, Civil & Environmental Engineering, Concordia University, Montreal,
Quebec, Canada
Mr Sohail Akhtar Department of Building, Civil & Environmental Engineering, Concordia University,
Montreal, Quebec, Canada
Mr Bin Xu Origin Geomechanics Inc., Calgary, Alberta, Canada
Laumontite-rich tight rock reservoirs are usually deeply buried and typically have low oil productivity
and quickly declining oil rates. Our previous experimental results indicate the compaction/dilation
nature of laumontite-rich tight rock under different stress conditions. Designing a suitable hydraulicfracturing scheme to enhance oil production in such laumontite-rich rock formation is challenging. In
this study, we applied finite element simulations to study the impact of rock compaction/dilation on
overall rock permeability in the lab and field scales. A soft rock plasticity model was applied tocharacterize the combined compaction and dilation yielding behaviors. The evolution of rockpermeability during loading was quantified using the plastic strain result from numerical simulations.
Fully coupled flow-deformation finite element simulations were also conducted to study the impact ofrock compaction/dilation on well productivity. The possibility of creating a field scale shear bandaround a hydraulic fracturing well was investigated.Laumontite-rich tight rock reservoirs are usually
deeply buried and typically have low oil productivity and quickly declining oil rates. Our previous
experimental results indicate the compaction/dilation nature of laumontite-rich tight rock under
different stress conditions. Designing a suitable hydraulic fracturing scheme to enhance oil production
in such laumontite-rich rock formation is challenging. In this study, we applied finite element
simulations to study the impact of rock compaction/dilation on overall rock permeability in the lab andfield scales. A soft rock plasticity model was applied to characterize the combined compaction anddilation yielding behaviors. The evolution of rock permeability during loading was quantified using
the plastic strain result from numerical simulations. Fully coupled flow-deformation finite element
simulations were also conducted to study the impact of rock compaction/dilation on well productivity.
The possibility of creating a field scale shear band around a hydraulic fracturing well was investigated.

ARC13-A-0129-Improvements of Using Adaptive Voronoi Mesh in the Rock Fracture Process:Computational Efficiency and Simulation Accuracy
Mr Jiacheng Song %#+ Southeast University, China
Prof He Lei Southeast University, China
The realization of numerical modeling based on the real structure of rocks is of great importance tostudy the fracture process and macroscopic mechanical behavior of rocks. One of the major problems
in building numerical models based on rock images is that it is difficult to achieve balance between thenumber of mesh elements and the similarity between the model and the images. Although limiting thenumber of mesh elements can improve the computational efficiency, the cost of doing so is often theloss of model similarity. The improvement of similarity is mostly achieved by increasing the numberof mesh elements, and it does not provide a good representation of the rock mineral grain boundary.
Therefore, it is of strong theoretical and practical significance to propose a modeling method that canbalance the number of mesh elements and model similarity while providing a good representation ofrock mineral grain boundaries.In this paper, various image processing techniques were applied to turnthe original rock image into image of feature boundary for post-processing. And then use the gradientdescent method to fuse the Voronoi polygon with the rock image according to the characteristics of the
pixel value changes in the grayscale map of the rock image. Finally, a high-quality model with a highdegree of similarity to the rock image and a relatively compact number of mesh elements is obtained.

Page | 36

This model was then used in the numerical simulation of Brazilian splitting tests, and the final results
were in good agreement with the experimental results and showed the advantage of the mesh inreproducing the crack extension of the rock failure process.

ARC13-A-0136-Numerical Manifold Method (NMM) Simulation Study On The Influence Of
Heterogeneity On Rock Failure
Mr Qi Lu %+ Southwest Petroleum University, China
Prof Youjun Ning # Southwest Petroleum University, China
Rock contains different mineral compositions as well as defects like microviods and microcracks,
showing significant heterogeneity. Forexample, even for the same batch of rock samples, thedeformation and failure experimental results have a certain degree of discreteness. In the present work,
based on the conventional Weibull random distribution model of material heterogeneity, the spatial
correlation scaling factor of heterogeneity is introduced to build the numerical model of rock witheffective description of the heterogeneity of real rock. By selecting different heterogeneity factor (m)values and spatial scale factor (&theta;) values, the obtained heterogeneity distribution in the numericalmodels are similar to the spatial distribution and microstructure of actual rock surface images.
Thereafter, the numerical manifold method(NMM),a numerical method that naturally represents
continuous and discontinuous problems in a unified framework, is usedto simulatethe compression
failure of heterogeneous disk and square numerical rock specimens. Results show that with thenumerical rock model considering the heterogeneity described by the heterogeneity factor and thespatial scale factor, the discreteness of deformation and failure behaviors of rock can be well
reproduced. In the future, the numerical manifold method will be used to further simulate and analyze
the effecting mechanism of heterogeneity on the deformation and failure of rock and its engineeringsignificance.

ARC13-A-0143-Numerical Modelling of the CRLD Cable and Its Application in Slope Movement
Monitoring-Dr Wen Nie %#+ Hebei University of Technology, China
Rock excavation is an essential phase in civil engineering projects. To reduce the vibrations andcompromise the safety, non-explosive rock breaking techniques have been developed as practicalsolutions for rock excavations close to residential and populated areas. In this paper, the application of
expansive chemical agents in rock excavation for deep foundation construction was analyzed using
discontinuous deformation analysis. By introducing the pressure histories as results of expansive
chemical agents mixing with water, the progressive rock breakages in moderately weathered granite
were simulated. The breaking efficiency was evaluated based on the expansion ratios of the holes andthe propagation of cracks in the rock block. Multi-holes patterns were considered to increase theefficiency of the application of expansive chemical agents on site.

Page | 37

ARC13-A-0156-3D Digital Reconstruction of Fractured Rocks and Multi-mineral Rocks
Mr Huaiguang Xiao %+ Southeast University, China
Prof Lei He # Southeast University, China
Digital rock physics is one of the most important methods to study rock mechanics and permeability
properties. This method mainly includes digital rock modeling and equivalent physical simulation.
Digital rock modeling is the premise to carry out high-quality equivalent physical properties
simulation. Previous research has focused on digital modeling for pore structure in small-scale shales
and sandstones. Moreover, the modeling for fractured rocks and multi-mineral rocks is only based on
inaccurate numerical models. In order to characterize the 3D structure of fractured rocks and multimineral rocks accurately, the 3D discrete fracture network (DFN) and multi-mineral rock digital model
are reconstructed from a single 2D surface digital image using the mathematical method. The 3D DFN
digital model based on the Markov random field and physical cover method can characterize thegeometric characteristics of natural fractures such as aperture, roughness and shape, and the fracture
proportion in the 3D model is similar to that in the 2D model. This 3D DFN digital model can provide
a reliable reference for analyzing rock permeability and mechanical stability. In addition, the 3D multimineral digital model based on the deep learning method can represent the geometry, distribution andmosaic relationship of natural rock grains, and the proportion of different grains in the 3D model issimilar to that in the 2D model. This multi-mineral digital rock model also can provide a reliablereference for analyzing the influence of mesoscopic heterogeneity on the macroscopic mechanicalresponse of rock.

Page | 38

SESSION TOPIC
S02 - ENVIRONMENT AND ENGINEERING GEOPHYSICS
ARC13-A-0034-Urban Seismology for Anonymous Monitoring of Urban Activities
Mr Gang Fang %#+ National University of Singapore, Singapore
Dr Yunyue, Elita Li National University of Singapore, Singapore
Dr Enhedelihai Nilot National University of Singapore, Singapore
Ms Yumin Zhao National University of Singapore, Singapore
Prof Arhur Cheng National University of Singapore, Singapore
Traditional urban activity monitoring based on cameras, although very effective with recent advancesin computer vision, raises severe privacy concerns. Urban seismic monitoring, which records vibrations
caused by human activity with geophones, has its natural attribute of anonymity. Here, we present acase study demonstrating the use of seismic method to monitor urban activities with less privacy
intrusion. We analyze the seismic signals recorded by a group of wireless geophones deployed on thecampus of National University of Singapore for the past year. Based on the spectral analysis of theseismic data, we characterize the seismic signals induced by different kinds of human activities,
including motor traffic, air traffic and foot traffic. For road vehicles, we observe strong energy across awide frequency band (0-200 Hz) on their seismic spectrograms, based on which we propose an
automatic motor traffic counting algorithm. For airplanes, we observe unique Doppler phenomena inthe spectrogram, from which we estimate flight parameters such as flight path, height, and speed. For
pedestrians, we observe spiky vibrations caused by footsteps, from which we estimate the cadence
information. After analyzing the seismic monitoring data, we observe a clear correlation between the
traffic activities leaving the NUS campus and the severity of the government’s restrictions during
Circuit Breaker and different phases of opening. Our study suggests that the anonymity of seismic
method enables high resolution monitoring of urban activity, which provide open and useful
information for evaluating the effectiveness of public policies, monitoring local human aggregation,and optimizing the use of public facilities.

ARC13-A-0066-Feasibility Study on Using Recycled Construction Waste Aggregate in Urban
Sponge Water Storage Structure
Mr Xue-tong Ma %#+ School of Geological Engineering and Surveying, Chang'an University, China
Mr De-bin Gao School of Geological Engineering and Surveying, Chang'an University, China
Prof Tonglu Li Chang'an University, China
To improve the utilization rate of recycled aggregate and provide safe and reliable building raw
materials for water storage structure of sponge City. The particle breakage and settlement deformationof recycled aggregate of construction waste with different proportions under different moisture content
and load after long-term drying and wetting cycles were studied through large-scale consolidation test.
The results show that the compression settlement of construction waste recycled aggregate is affectedby load, moisture content and drying and wetting cycles, and the proportion of aggregate also has acertain influence on the settlement. With the increase of load and the times of drying and wetting cycles,
the compression settlement of recycled aggregate increases. With the increase of the proportion of brickaggregate, the compression settlement increases. When the moisture content is the optimal moisture
content, the compression settlement is the largest. It can be considered that the settlement of aggregate
is mainly caused by particle breakage, and other factors affect the compression settlement by affecting
particle breakage. Particle breakage is the fundamental reason for the settlement of recycled aggregate.
Based on the experimental results, the empirical formula of aggregate ratio, moisture content, load andsettlement under the action of drying and wetting cycles is established. According to the characteristics
of water storage structure in sponge City, the appropriate construction scheme is put forward.

Page | 39

Considering that the actual application load of water storage structure is small, the post construction
monitoring program is converted to pre construction prediction. In terms of construction feasibility,
recycled aggregate is a reliable raw material for the filling of sponge city water storage structures.

ARC13-A-0100-Dynamic Monitoring of Co2 Sequestration and Plume Motion with Advanced
Seismic Imaging%#+
Prof Ping Tong
Nanyang Technological University, Singapore
Geological storage of CO2 in a deep saline aquifer is a promising way to reduce the emission ofgreenhouse gas to the atmosphere. This is a critical approach for the success of the Net-Zero 2050 goal
set by many major industrial countries. Storage of CO2 requires monitoring of the induced seismicity,
the plume extent and the potential stratigraphic seal failure. All of these can be accomplished by using
advanced seismic imaging techniques. Seismic traveltime tomography is a routine imaging technique
to investigate structural heterogeneities and geodynamics of the Earth’s interior. Ray-based seismic
traveltime tomography is simple and easy to be implemented. But ray tracing may be inaccurate evenin mildly heterogeneous model. Full waveform inversion is physically more correct and maintains its
accuracy in complex media. However, a good knowledge of earthquake sources and structure is an
essential requirement for the accurate measurement of the misfit between synthetic and observed
waveforms. In addition, full waveform inversion is computationally expensive. We present a third formof seismic traveltime tomography, which is neither ray-based nor wave-equation-based. In detail,seismic traveltime tomography is formulated as an eikonal equation-constrained optimization
problem, which is solved by the adjoint-state method. For both isotropic and anisotropic media, we
discuss adjoint-state absolute traveltime tomography, adjoint-state common-source double-difference
traveltime tomography, and adjoint-state common-receiver double-difference traveltime tomography.
The advantages of these methods include (1) accurate computation of traveltime fields in complex
media, (2) using the most reliable seismic data traveltime, (3) correctly reflecting the relation between
the traveltime data and subsurface structure, and (4) the double-difference traveltimes have strong
resolving ability of the subsurface heterogeneities. All these imaging techniques will be applied tomonitor the dynamics of CO2 storage and plume motion.

Page | 40

SESSION TOPIC
S03 - ENVIRONMENTAL PROCESSES IN GEOTECHNICS
ARC13-A-0114-Physical Disintegration of Mudrock Samples in Hambalang Area, Bogor, Indoesia
Mr Misbahudin Misbahudin %#+ Universitas Pertamina, Indonesia
Many of the infrastructure buildings are built on a foundation from sources of mudrock. Hambalang,
Bogor, Indonesia is an area that has projected infrastructure buildings, including national sports
facilities and housing for residents. Previous reports have stated that construction problems mainly
originate from unstable foundation material due to the presence of mudrock and its weathering
product. Mudrock can be evaluated for its disintegration characteristics through immersion and drying
which minimizes mechanical forces. The research was conducted by testing the physical disintegrationof several mudrock samples from Hambalang, to later become an engineering consideration in ongoingor future infrastructure activities. The test is mainly the preparation of rock samples weighing 450-550
grams which are dried in sun exposure for two days. The samples were then immersed in a water-filled
beaker for 24 hours. Series of tests for the physical properties of rocks were also carried out to obtainwater content, dry density, porosity, and absorption.Based on the disintegration index value that has
been obtained, the quantitative approach shows that all samples have a high index. This indicates low
disintegration characteristics. This is different when observed physically through immersion tests. The
intact sample has mostly deteriorated into angular fragments that show clear evidence of thedisintegration of the rock. Further review is needed regarding the characterization of mudrock
disintegration in Hambalang. Field observations with visual during immersion observations show
similar conditions in the form of disintegrated rocks.

ARC13-A-0142-A Design Concept for Wells Screen During Combined Strata Dewatering withDifference Hydraulic Permeability
Dr Xiaotian Liu %#+ Tongji University, China
Prof Wang Jianxiu Tongji University, China
Ms Na Xu Tongji University, China
With the comprehensive implementation of "deep earth exploration" in China, urban undergroundspace development has been further improved, more and more environmental problems come withgroundwater control in deep excavations. Especially in built-up areas, how to balance groundwaterlevel on both sides of foundation pit and control ground settlement become a hot research topic.
However, without the guidance of a perfect theoretical foundation, engineers can only explore somefoundation pit dewatering design ideas based on personal experience. "Layered dewatering" was firstly
put forward in the process of foundation pit dewatering on Yishan Road station of Shanghai MetroLine 9, when obviously hydraulic differences exist between layer ⑤
3-2 (silty clay) and layer ⑦
2 (finesand). However, design concept of wells screen between two connected aquifers with difference
hydraulic permeability is still unclear, and usually causes excessive exploitation of groundwater. In thispaper, based on the analysis of shallow geological conditions in Shanghai, five kinds of combined strata
with difference hydraulic permeability are summarized, and six dewatering design concepts are put
forward. Based on the numerical simulation and comparison analysis of foundation pit dewatering
design scheme on Biyun Road station of Shanghai Metro Line 14, the optimization design scheme ofwells screen structure is put forward, and the total pumping volume of foundation pit is reduced by
13%.

Page | 41

SESSION TOPIC
S04 - ENGINEERING GEOLOGY FOR TUNNELS AND UNDERGROUNDCONSTRUCTION
ARC13-A-0059-Sustainable UUS Induced-Land Subsidence and Economic Spatial Planning Model:
the Extent Development Impact
Mr Muhammad Akmal Hakim bin Hishammuddin %#+ Tongji University, China
Prof Wang Jianxiu Tongji University, China
This paper presents the extent impact of urban underground exploration (UUS) induced-landsusbidence to economic factors (i.e buildings, land, infrastructures and underground structure) in termsof urban development, spatial model planning towards sustainable development in a developed
megacity of Shanghai. Currently, there are no determined integrated researches conducted tounderstand the correlation of UUS induced-land subsidence with the economic impact despite its
significant role in the urban planning and development at large scale. Secondary data are analysedusing hedonic pricing method, multiple regression method, correlation cause effect analysis andspatial-temporal analysis. The data are gathered from online databases: Google, Google Scholar, Baidu,
ResearchGates, Elseviers and etc. There are more than 100 prominent journal articles have beenreviewed for the data synthesis. The time-frame ranges as early as 1960s-90s, 2000s till 2020. The
negative spatial corelation hyphothesis of the economic impact and UUS induced-land subsidence has
been proven both similar and contradictory in different areas of Shanghai. The findings are (1) most of
the land subsidence and economic impact in central bussiness district (CBD) area of Shanghai are still
under controlled due to proper UUS technologies, (2) The new development area of Shanghai (Northand Southern) has negative correlation due to the UUS induced-subsidence with the economic factors(3) New development areas are prone for future UUS-induced subsidence therefore, the economic
impact may be affected without proper planning and underground exploration countermeasures (4)The economic impact of Shanghai has been influenced by many factors and UUS induced-subsidence
are becoming the highest impactful factor (5) In the case of developed and rapid continous urbanisation
like Shanghai, groundwater is controlled however, further data collection is needed to makecomparison with other developing megacity in South East Asia region with rapid land subsidence
issues such as Jakarta. As conclusion, these preliminary findings open up for further research work andquestions to be conducted to assists future urban planners, geotechnical engineering in the developed
megacity like Shanghai as well as making future comparison with developing megacity, e.g. Jakarta intackling the UUS, land subsidence, economic impact towards sustainable spatial development modeland planning.

ARC13-A-0079-An Image Analyzing Method for Quantitative Evaluation of Crack Spacing in
Tunnel Faces
Dr Hayato Tobe %#+ Kajima Corporation, JapanMr Yasuyuki Miyajima Kajima Corporation, JapanMr Daisuke Fukushima Kajima Corporation, Japan
Appropriate construction of tunnel requires quantitative and immediate evaluation of properties of theface. The properties consist of several factors, such as strength of bedrock, weathering grade, directionof cracks, and spacing of cracks. Traditionally, the evaluation of these factors has been performed
mainly by visual observation by civil engineers. The results of the evaluation have been often not
quantitative. In recent years, advances in information technology have led to the development oftechniques for quantitatively evaluating the strength of bedrock and the weathering grade rapidly.
Quantitative measurement of the direction and the spacing of cracks has become possible by applying
laser surveying and photogrammetry. However, these techniques are often insufficient for the purpose

Page | 42

of immediately measuring the direction and spacing of cracks on site because it takes more than ten
minutes for analysis. Therefore, we have developed a new method to measure the crack direction andspacing of bedrock quickly and quantitatively by image analysis. This method measures the spacing of
cracks by the following four procedures: at first, cracks of the tunnel face are extracted from thephotograph of the tunnel face based on the difference in brightness; secondly, the image of cracks isdivided into small meshes; thirdly, the dominant direction of cracks is detected in each mesh; andfinally, the cracks in the mesh are scanned in the direction orthogonal to the dominant direction andspacing of cracks are measured. We applied this method to an actual tunnel face and were able tomeasure the crack spacing of the face in approximately ten seconds.

ARC13-A-0080-Experimental Study on Evolution Process and Failure Mechanism of Overlying
Strata in Coal Mining Based on Distributed Strain Sensing Technology
Dr Lei Zhang %+ Tsinghua University, China
Prof Yifei Cui # Tsinghua University, China
Prof Bin Shi Nanjing University, China
Prof Yan Yan Southwest Jiaotong University, China
Dr Heming Han Nanjing University, China
The failure of overlying strata in coal mining threaten the safety of roadway and may further induce
underground water inrush accidents. Therefore, the deformation monitoring of overlying strata is ofgreat significance. In order to investigate the evolution process and associated failure mechanism ofoverlying strata under the action of mining, a physical similarity model test was constructed. The
distributed strain sensing technology (DSS) and close-range photogrammetry (CRP) technologies wereadopted to record the internal and surface displacement information of the model test during coalmining. By comparing the deformation recorded by CRP technology and DSS cables, the feasibility of
DSS technology is demonstrated and even though the deformation is small, the DSS technology canstill detect strain variation. According to the CRP result, it is found that the deformed area is saddleshaped in general, forming symmetrical step-shaped fissures at mining face and the initial position ofmining. Through analyzing the strain exerts on the DSS cables when the mining face approaches andpasses through the installed DSS cables, the deformation characteristics and failure mechanism ofoverlying strata is addressed and the shear failure appeared at the toe area of key layer may result inthe overall collapse of the overlying strata. This study provides practical significance in deformation
monitoring and sheds insight into the failure mechanism of overlying strata under coal mining.

ARC13-A-0104-The Log-GSI Method to Estimate GSI from Borehole Data: Application in Snowy
2.0 Project
Dr Manfred Thüring %# Lombardi Engineering Ltd., Switzerland
Mr Alberto Vanni Lombardi Engineering Ltd., Switzerland
Mr Davide Vietti Lombardi Engineering Ltd., Switzerland
Dr Emanuele Catalano Lombardi Engineering Ltd., Switzerland
Dr Antonio Dematteis Lombardi Engineering Ltd, Australia
Since its introduction in 1994, the Geological Strength Index (GSI) has become a popular tool to describe
the rock mass condition, particularly due to its link to the previously introduced Hoek-Brown failure
criterion which allows to estimate the major design parameters for underground excavation projects(shear strength and deformability).The GSI assessment is usually based on the visual inspection of arock surface (outcrop, tunnel face, etc.). However, in the design process of underground works theavailable information at project depth is rather contained in boreholes, practically the informationneeds to be assembled from the recovered rock cores, their pictures and logged information.Among

Page | 43

others, Hoek, Carter and Diederichs in their paper &ldquo;Quantification of the Geological Strength
Index Chart&rdquo; (2013) have prepared the way for a quantitative evaluation of the GSI, in terms of
RQD for the rock mass segmentation and a few alternative ways of describing the discontinuity quality,
in terms of Bieniawski’s RMR (Jcond89) or Barton’s Q (Ja, Jr) system. Whereas the RQD is commonly
available from borehole logging, the description of the joint condition is usually a more narrative
aspect.We present the experiences during the design studies of the deep tunnels of the hydroelectric
pumped-storage project Snowy 2.0 (New South Wales, Australia), in which the GSI was determinedfrom borehole logging and the rock mass strength and deformability parameters were calculated by
the Hoek-Brown criterion.The borehole logging was done according to the Australian geotechnical site
investigations standard AS 1726-2017. A procedure was developed to translate the descriptions of thejoint condition into Barton’s Ja and Jr. The GSI was finally determined according to Hoek et al. (2013)
and was compared to and validated by directly logged Ja and Jr values and a visual inspection of therock cores.The methodological approach, its results and a critical analysis are presented and discussed
for 3 boreholes of differing lithology and rock mass quality (good, fair and poor). An outlook is given
for the further usage of the outcomes in the design process of underground excavations.

ARC13-A-0127-Better Use of Abandoned Oil/gas Wells and Small Lng Stations
Prof Hezhen Yang %# Singapore Institute of Technology, Singapore
Dr Fei Xiao + Department of Civil Engineering, Nanjing University of Aeronautics and Astronautics,
Singapore
There are a huge number of abandoned oil/gas wells (AO/GW) all over the world, which can be harmful
to the environment if not being treated in a proper way, while the corresponding treatment cost could
be high. To address this issue in a more economical way, it is proposed to revitalize AO/GW via
geothermal energy exploitation. Considering that the bottom hole temperature of AO/GW is usually
low and medium, enhancement of the associate thermal performance is in need. It is known that extra
heat should be added to facilitate the regasification of liquified natural gas (LNG) in small fuel stations,which could result in a waste of cold energy. Therefore, if it happens that a small LNG station issurrounded by one or several AO/GWs, geothermal energy exploitation and a small-scale gas turbine
can be integrated into the regasification process through a binary cycle system, then the geothermal
resources from AO/GWs can be better harvested due to larger temperature difference created, and thenatural gas produced can be used to generate electricity first before going to the end users. The purposeof our work is to explore the variation patterns of regasification capacity of LNG station in terms of thecharacteristics of an AO/GWs, including different thermal conductivity of AO/GW structure and thesurrounding formation, temperature gradient and depth of formation, and working fluids and theassociated circulation velocities. Then a predictive model using system characteristic parameters will
be built to evaluate the maximum regasification capacity under given working conditions.

Page | 44

ARC13-A-0137-Design and Implementation of Integrated Monitoring System for Deep Tunnel
Sewerage System Phase 2 (DTSS2) Project in Singapore
Dr Aung Ko Ko Soe %#+ DTSS2 Department, National Water Agency, PUB, Singapore
Ms Lai Lynn Woo DTSS2 Department, National Water Agency, PUB, Singapore
Dr Kyi Khin DTSS2 Department, National Water Agency, PUB, Singapore
Mr Simon Yim DTSS2 Department, National Water Agency, PUB, Singapore
Mr Darryl Tan DTSS2 Department, National Water Agency, PUB, Singapore
Dr Angus Maxwell Maxwell Geosystems, Singapore
Mr Elpidio Valdez. Jr Maxwell Geosystems, Singapore
Singapore’s DTSS2 project comprises 50 km of tunnelling by 19 Tunnel Boring Machines (TBM) andanother 50 km of link sewer pipe jacking work at depths between 35 to 55m below the surface to channel
used water to a new centralised water reclamation plant to be constructed in Tuas. Deep tunnelling
works inevitably cause disturbance to surrounding ground and the DTSS2 construction in built-up
urban environments represents a significant risk to existing structures. As such, TBMs used on the
project are heavily instrumented to achieve better control in operation. Every work activity is designed
to be monitored with arrays of geotechnical instruments and other sensing providing data at all times.
The data volume is expected to be large and to efficiently manage and utilise these data, Singapore’s
National Water Agency, (PUB) devised, procured and implemented an integrated monitoring system
known as the Shaft and Tunnel Excavation Monitoring System (STEMS). STEMS is a bespoke webbased data management system configured in accordance with project specifications and requirements.
It is designed to streamline continuous progress and production data flows from TBMs, pipe jacking
and shaft sinking machines and integrate with various other monitoring data sources, soil investigation
data and construction information. After near real time processing, quality engineering data isdelivered in a timely manner, with on-the-fly integration tools for analysis and interpretation. In
addition to core monitoring features such as data visualization, reporting and automatic alert
messaging, the system also computes and presents detailed construction progress and completion
status of every shaft excavation and TBM drive. The statistical breakdowns of work activities are alsoavailable and therefore data transparency is improved with more reliable delivery and accuracy.
Moreover, real-time display of TBM parameters and digitalization of various construction data withcentralized storage on a common data server offers instant and convenient access to construction
managers, supervision teams and engineers to make fast and correct decisions. The system is provento be effective for urban tunnelling projects and to positively impact construction efficiencies. This
presentation outlines the architecture, functionalities and some key benefits of implementing STEMSin the DTSS2 Project.

ARC13-A-0157-Sprayed Concrete for the 21st Century
Mr Cheng Chian Gan %#+ Bekaert Singapore Pte Ltd, Singapore
In recent years, fibre reinforced concrete (FRC) has been used in underground construction for sprayedconcrete in underground support linings. The evenly distributed fibres contributed to considerable
increase in load-bearing capacity, durability and impact resistance. This paper aims to present thedefinition, design, performance specification and the latest QA/QC test methods of sprayed FRC. The
QA/QC requirements will also be in line with the latest Singapore Standard SS 674: 2021 - Design offibre concrete structures.

Page | 45

SESSION TOPIC
S05 - KARST GEOLOGY AND ENVIRONMENTAL GEOTECHNICS
ARC13-A-0030-Microscale Structural Deterioration of Intact Loess Under Acid and Saline
Solutions and Resultant Macroscale Mechanical Properties
Prof Wen-Chieh Cheng %#+ Xi'an University of Architecture and Technology, China
Dr Wenle Hu Xi'an University of Architecture and Technology, China
Dr Shaojie Wen Xi'an University of Architecture and Technology, China
Prof Md Mizanur Rahman University of South Australia, Australia
Chemical contamination not only can cause environmental problems but also lead to a notable change
in the mechanical properties of soil. Loess distributed over NW China is featured with metastablestructure, and chemical contaminants induced by rapid urbanisation in recent years notably threaten
the fragile loess environments. The microscale structural characteristics of the loess and the impacts on
the macroscale mechanical properties, when exposed to chemical contaminants, are deemed critical forchemical-contaminated land reclamation. In light of this, the microscale structural characteristics of theloess specimens exposed to acetic acid and sodium sulfate respectively are studied using scanningelectron microscopy, X-ray diffraction, and energy dispersive spectroscopy analyses. Further, theirmacroscale mechanical properties are determined by direct shear tests. The mechanism to lead to themicroscale structural deterioration, when exposed to chemical contaminants, is revealed; the corrosionof the cement between particles caused by hydrogen ions when subjected to acetic acid environments
and the salt-induced swelling phenomenon under saline conditions play a leading role in the microscale
structural deterioration. The resultant macroscale mechanical properties show excellent
correspondence with the deteriorated structural characteristics. The findings of this work provide key
guideposts for chemical-contaminated land reclamation in NW China.

ARC13-A-0051-Strength Deterioration Mechanism of a Typical Soft and Hard Interbedded Rock
Mass in Three Gorges Reservoir Area Under Wetting and Drying Cycling Condition
Prof Qiong Wu %#+ Faculty of Engineering, China University of Geosciences, Wuhan, China
Ms Di Wang Faculty of Engineering, China University of Geosciences, Wuhan, China
Prof Huiming Tang Faculty of Engineering, China University of Geosciences, Wuhan, China
Mr Jintao Kang School of Qilu Transportation, Shandong University, Jinan, China
Mr Zhen Meng Faculty of Engineering, China University of Geosciences, Wuhan, China
Ms Xiaoxue Huo Faculty of Engineering, China University of Geosciences, Wuhan, China
Ms Yuxin Liu Faculty of Engineering, China University of Geosciences, Wuhan, China
Mr Shiyu Li Faculty of Engineering, China University of Geosciences, Wuhan, China
Due to cyclic reservoir water level fluctuations, rock mass in hydro-fluctuation belt of reservoir bankare subjected to wetting and drying cycles, which is detrimental to the stability of bank slope. In thisstudy, the strength deterioration mechanism of soft and hard interbedded rock mass under wetting anddrying cycling condition are investigated by taking atypical sliding-prone rock mass with silty
mudstone and argillaceous siltstone interbedded of the Badong formation in the Three Gorges
Reservoir as the research object. The degradation equations of strength parameters of silty mudstone,
argillaceous siltstone and bedding planes between these two rock types under wetting and drying
cycling conditions are firstly established through a series of laboratory experiments. Based on theseobtained degradation equations, uniaxial/triaxial compression numerical experiments were thencarried out to study the contribution of strength degradations of rocks and bedding plane to thecompressive strength degradation of soft and hard interbedded rock masses and its relationship withthe dip angle and confining pressure. The results indicate that the influence of strength degradation ofrocks and bedding planes on the compressive strength degradation of soft and hard interbedded rock

Page | 46

masses are obviously varied with dip angle, which can be divided into range of controlling by soft rock,range of controlling by combination of soft rock-hard rock-bedding plane, range of controlling bybedding plane and range of controlling by hard rock. The influence of confining pressure on thecontribution of strength degradations of rocks and bedding plane on compression strength degradationof soft and hard interbedded rock mass varies with the dip angle, while the confining pressures in a
relatively low level used in this study have little impact on the limits of dip angle partitions bydeterioration mechanism. Based on the data acquired from the numerical experiments, the equation toestimate the compression strength of the typical soft and hard interbedded rock mass of the Badong
formation under wetting and drying cycling condition was developed.

ARC13-A-0160-Characterization of Geological Targets in Karst Terrains with Seismic Arrays
Prof Lanbo Liu %#+ Department of Civil & Environmental Engineering, United States
Globally, the widely extended karst terrains poses great challenges to urban development,
groundwater resources, waste water contamination control, and subsurface geotechnical engineering.
Narrow down to geotechnical engineering, sinkholes, dissolved channels and networks, caves andvoids certainly complicate the design, construction, and maintenance of any projects sited in karst
geology. As an indirect and cost-effective approach, the seismic method using both active and passive
sources and deployed either on land surface, or in underground in tunnels or boreholes, or evensimultaneously on both surface and subsurface, is one of the most powerful tools to provide credible
information of karst environments, in conjunction with the direct excavation by drilling, trenching, andtunneling.In this talk I will survey and review the effectiveness of a variety of seismic array
configurations and seismic source and wave types for tackling the challenge of detection of differrent
geological targets in karst terrains. I will illustrate the arguments with numerical simulated cases.
Apparently, surface arrays are most effective for laterally extended features like underground rivers;
while vertical seismic profiling (VSP) may by more useful for imaging the vertical conduits. A
combination of using surface array and array in tunnels may provide more tightly constrained
information for imaging the targets in front of tunnel face. In really the challenge is timesynchronization of the subsurface and surface arrays.

ARC13-A-0161-Research Progress of Geological Forward Prospecting with Seismic Method in
Hard-rock Tbm Tunneling
Dr Lei Chen %#+ Shandong University, China
Prof Bin Liu Shandong University, China
More and more hard-rock TBMs are applied worldwide for underground projects in the field oftransportation,water conservancy, andmining, etc. However, hard-rock TBM has poor adaptability toadverse geology, such as faults, karst caves and fractured zones. Without identification of adverse
geology in advance, TBM tunneling may encounter geo-disasters such as water inrush, collapse andlarge deformation. Detection of these adverse geologies is an important prerequisite for the safe andefficient construction of TBM tunnels. In this talk, an active seismic method and a seismic whiletunneling method will be introduced to address this requirement. For TBM maintenance stage, theactive-source seismic prospecting method based on 3D observation method, the velocity inversion anddepth-domain migration methods was developed; and for TBM drilling stage, the seismic detection
using TBM drilling noise was improved to achieve the real-time forward-prospecting. Both methods
can provide imaging of karst caves and fault within 100m ahead. The detection results are directly
presented to better guide tunneling.The method has been successfully applied in field, including
Yinsong Water Supply Project, the longest tunnel in Asia&mdash;Yinhanjiwei Project as well as thelongest railway tunnel in China&mdash;Gaoligongshan tunnel in Yunnan province, etc. In this talk,Page | 47

the typical application cases will presented. On-site applications indicate the method can successfully
detect major geological structures and effectively protects safety.

ARC13-A-0164-Cross-hole Resistivity Fine Detection Method for Urban Underground Adverse
Geology and Its Application
Dr Zhengyu Liu %#+ Shandong University, China
At present, the development of Deep-earth, Deep-sea and Deep-space has been taken as a major
national science and technology innovation strategy, while the detection of underground space
utilization layer is one of the four major objectives for the Deep-earth plan. Several mature detection
techniques have been developed for larger-scale adverse geology such as faults and karst. However,small-scale adverse geology such as small boulders, pebbles, dissolution pipes and caves are likely to
induce serious urban geological disasters and environmental problems. The fine detection andmonitoring of these geology are gradually becoming an urgent need.In this talk, a fine-imaging
inversion method and a monitoring method based on cross-hole resistivity method will be introduced,
which will effectively solve the needs of fine detection and monitoring of small-scale adverse geology.
In terms of fine detection, a multi-scale inversion method based on convolutional wavelet transformhas been developed to successfully solve the boundary inscription problem in resistivity inversion. In
terms of monitoring and imaging, a dynamic reorganization strategy of monitoring data has been
innovated, and data weighting and temporal regularization constraints have been introduced toeffectively realize monitoring and imaging of subsurface water transport.The method has beensuccessfully applied in practical projects, including Xiamen rail transit project, Guangxi Cenxi tunnel
project, Jilin Yinsong project, Yunnan Dehou reservoir and a number of other vital projects. The field
application shows that the method can effectively realize the fine detection and monitoring imaging ofunderground adverse geology, and effectively protect the engineering safety.

Page | 48