International Press-in Associationwww.press-in.org

Volume 9, Issue 2

I NSIDE T HIS I SSUE

Message

1. Message (P1)

From the Director

June 2024

From the Director
2. Upcoming ICPE2024 (P2)

Yukihiro Ishihara

3. Special Contribution (P5)Center Director, Press-in Technology R&D Center, GIKEN LTD.

4. Director’s Research &Activities (P10)
5. Reports (P14)
6. Event Report (P16)
7. Young Members (P18)
8. Event Diary (P20)
9. Corporate Members (P21)
10. Editorial Remarks (P23)

EDITORIAL BOARD
Nor Azizi Bin Yusoff
Michael Doubrovsky
Ramin Motamed
Chun Fai Leung
Pastsakorn Kitiyodom
Anh Tuan Vu
Mark Albert H. Zarco
Shinji Taenaka
Adnan Anwar Malik
Chen Wang
Tsunenobu Nozaki
Daisuke Hirose
Hongjuan He
Maki Kato

I have been impressed and inspired by the strength of IPA in
pursuing the fusion of theory and practice, since I joined GIKEN
and the IPA community in 2007. This pursuit, I believe, stems
from the strong awareness of Mr. Akio Kitamura, Emeritus
President of IPA, and I have been honored to haveopportunities of feeling his love and dedication for the press-in
technology. I also feel happy for being engaged in thecollaborative research between the University of Cambridge and GIKEN, which has
been lasting since 1994 with a great support from Dr. Malcolm Bolton and Dr. Stuart
Haigh. In addition, I had another luck of contributing to further strengthening theacademic function of IPA, which was strongly pushed forward by Dr. Osamu Kusakabe
and was made possible through the efforts of IPA Secretariat at the time including Mr.
Kazuyoshi Ishii, Ms. Mutsumi Minami, Mr. Masafumi Yamaguchi and Ms. Hongjuan
He. The first international conference (ICPE2018, Kochi) at Kochi University ofTechnology was the symbolic event to me in this viewpoint.
There are mainly two perspectives in our research team. One is the technology ofutilizing information during the press-in construction work, and another is theperformance of embedded structures constructed by the press-in method. An
essential point is a good understanding on the soil-pile interaction throughout theprocess of construction and service. For
this, we adopt various researchmethodologies such as the monitoringand observation at the actual construction
sites, field testing, outdoor large-scalemodel testing, indoor model testing andnumerical analyses. We are taking
advantage of diverse human resource andFig. 1. Research team and Researchinnovative environment (Fig. 1), to tackle
Building in RED HILL 1967
with many challenging issues on our way.
The third international conference next month (ICPE2024, Singapore) is the firstacademic conference on Press-in Engineering that is to be held outside of Japan, andwill be a new experience to the IPA community. Our research team are eager tocontribute through more than 10 papers and presentations. I appreciate all the
preparatory work by the conference organizers and the IPA Secretariat, and am
looking forward to the oncoming interactions with the participants in this conference.

◆ A brief CV of Dr. Yukihiro Ishihara
Dr. Yukihiro Ishihara is Center Director, Press-in Technology R&D Center, GIKEN LTD.
After getting Bachelor’s and Master’s degrees in Civil Engineering at the University ofTokyo (UTokyo) in 2005 and 2007, he joined GIKEN and has been engaged in R&D
activities on the press-in piling process and the pressed-in structures. He received a
degree of Doctor of Engineering at UTokyo in 2023, on the use of press-in piling data
for estimating subsurface information and pile capacity. He has been Director of IPA
since 2017.
1Volume 9, Issue 2

June 2024

Upcoming ICPE2024, Singapore: Call for participants
Chun Fai Leung
PresidentInternational Press-in Association

Call for participation


ICPE2024 Website: https://2024.icpe-ipa.org/
Regisration Site: https://www.press-in.org/en/event/application/input/39

The Third International Conference on Press-in Engineering (ICPE2024) will be held in Singapore from 3 to 5 July 2024.
Press-in piling and engineering works are now commonly employed in many countries. These kind of works are expected
to grow further to achieve sustainability and resilience of infrastructure against climate change. As an example, strong
coastal and river protection works become necessary in many countries to tackle rising sea level and erratic climate
conditions such as flooding and stronger wave forces. In view of the above, the theme of ICPE2024 is ‘The Superiority ofPress-in Piling towards Sustainable Construction in Tackling Climate Change for Infrastructure Development’.
Two keynote speakers will deliver lectures on the conference theme. Dr. SY Yamaguchi of the United Nations University
Japan will present the ‘Progress of United Nation’s Sustainabe goals and the Synergy with Climate Change Actions’.
Professor Ken Gavin of the Delft University of the Netherlands will present ‘The Potential Use of Press-in Methods in the
Offshore Renewables Industry’. There will be also be a Singapore Theme Lecture to be delivered by three prominent
practicing engineers, Dr TL Goh and Mr David Liaw of Singapore and Mr T Nozaki of Japan. They will share their knowledge
on ‘Development of Press-in Technology in Southeast Asia with Applications on Coastal Protection’. In addition, there will
be a special Southeast Asia session with presentations given by prominent researchers/engineers from the region.
ICPE2024 offers opportunities for academics and technicians to intercommunicate with one another and for students andyoung experts to present their achievements. The ICPE would be grateful to welcome your participation. We would also
appreciate your help in disseminating information of this event to your colleagues. We look forward to seeing you at theconference and finding common ground with you.
2

Volume9, Issue
2 June 2024
Volume7, Issue
3 September
2022
Program:Day One: Wednesday, 3 July
SGT
(UTC+8)
8:30

Lobby

9:00

Coffee Break 10:00～10:30
Keynote Lecture 1 10:30-11:30

14:00
15:00
16:00

Keynote Lecture 2 11:30-12:30
Exhibition

Registration

11:00

13:00

Hall 1 (LT50)

Welcome and Opening 9:00-10:00

10:00

12:00

Main Hall (Auditorium 2)

Lunch 12:30～13:30
Session A-1
Pile Performance/Piling Mechanism
13:30-15:00

Session B
Climate Change/Infrastructure Development

13:30-15:00

Coffee Break 15:00～15:30
Session C-1
Disaster Prevention and Mitigation
15:30-17:00

Session D-1
Project Case Histories/Miscellaneous
15:30-17:00

17:00
18:00

Banquet (18:00~)

Kent Ridge Guild House3

Volume9, Issue
2 June 2024
Volume7, Issue
3 September
2022
SGT(UTC+8)
8:30

Lobby

9:00

Main Hall (Auditorium 2)

Hall 1 (LT50)

IPA Handbook (Press-in Retaining Structure - Design & Construction) 9:00-9:40
Theme Lecture 9:40-10:30

10:00

Coffee Break 10:30～11:00
11:00

Special Singapore Southeast Asia Session

14:00
15:00
16:00

Exhibition

13:00

11:00-12:30

Registration

12:00

Session E
Infrastructure Development
11:00-12:30

Lunch 12:30～13:30
Early Career Engineer Presentation

Session A-2
Session A-3
Pile Performance/Piling Mechanism
Pile Performance/Piling Mechanism
Coffee Break 15:00～15:30
Session C-2
Disaster Prevention and Mitigation
15:30-17:00

Session D-2
Project Case Histories/Miscellaneous
15:30-17:00

Closing Remarks 17:00-17:10

17:00

Day Three: Friday, 5 July
SGT
(UTC+8)
9:30

Registration

10:00

Press-in Piling Live Demonstration

11:00
12:00

1. Zero Clearance Method : Zero Piler JZ100
2. Press-in assisted with Augering : Silent Piler F111 (Crush Mode)
3. Rotary Press-in Piling Method : Gyro Piler SP12 (GRV1230)
Note:1) Location : 17 Gul Way, Singapore 629194 (Guan Chuan Engineering Pte., Ltd.)2) The demonstration includes refreshments.

4Volume 6, Issue 2

June 2024

Special Contribution

Residual bearing capacity of scoured shallow foundations andtheir reinforcement effect by press-in sheet piles
Hidetoshi Nishioka
1. Introduction

Professor, Department of Civil and Environmental Engineering
Chuo University

There have been increasing cases of damage to bridges thatcross rivers as flood disasters have become more severe due toclimate change in recent years. Many of the bridges built inJapan prior to World War II are still in use today, but many ofthese bridges are supported by shallow-spread foundations orwood piles, making them particularly susceptible to scouring.
Large displacement occurs in scoured foundations, making thebridge impassable even if the bridge does not collapse. The
following two contradictory points need to be consideredwhen managing the restoration of bridges, which areimportant infrastructure, for a country or local community tosteadily rebuild after a disaster. The first is for paths to be madetemporarily accessible as soon as possible after a disaster, evenin cases of limited performance to some extent. The second isto ensure the structure to be strengthened so that the damage
does not happen again.
This article introduces examples where this form ofmanagement was successful in railway bridges in Japan [1],[2].
Fig. 1 shows the situation during flooding, where a shallow
foundation was scoured, resulting in a residual settlement ofapproximately 300 mm and a residual inclination of
approximately 50/1000. Emergency restoration was
implemented at an early stage (approximately one month after
the disaster) after confirming with loading tests up to 90% of
the maximum train load (Fig. 2) that the structure had theminimum bearing capacity to withstand slow train operation.
In this case, in exchange of forgoing foundation reinforcement
work, train speeds were restricted, and an electronicmonitoring system was also used, thereby ensuring safety.
Afterwards, steel pipe piles were pressed in around thescoured foundation in order to reinforce and integrate thestructure (Fig. 3). These types of reinforcement work were
carefully conducted during periods of low rainfall (autumn andwinter in Japan) while trains were running. The reinforcement
work was completed, and the train speed restrictions andelectronic monitoring systems were lifted approximately six
months after the disaster.
Generalizing this form of good practice experience requires
clarifying the mechanism by which the residual bearing
capacity of shallow foundations is expressed even after being
damaged by scouring and establishing quantitative design
methods for the reinforcement effect by press-in sheet piles. In
this article, we introduce model experiments using an
aluminum-rods model ground that we are conducting for these5Fig. 1. View during the flood [1]Fig.2. View of Static loading test by water tank [2]

Fig.3. General drawing of the restoration withPress-in Steel pipe piles [1]Volume 6, Issue 2

June 2024

purposes.

2. Overview of experimental technology using aluminum-rods model ground
The aluminum-rods model ground is a mixture of aluminum rods (specific gravity 2.7) of different diameters of several
millimeters and stacked together with the rods aligned in the same direction as shown in Fig. 4, where a two-dimensional
granular material is simulated. The nonlinearity of the stress-strain relationship and the dilatancy properties are similar
to those of a medium dense sand. Another major advantage is that the information on displacement and porosity changes
in the model ground can be easily obtained from the end face of the aluminum rod through image analysis. Because of
these features, aluminum-rods model ground has sometimes been used as one of the basic techniques for conducting
model experiments targeting two-dimensional boundary value problems in the field of geotechnical engineering sincethe 1960s[3],[4].
Enlarged view
In this experiment, we used a mixture of three types ofaluminum rods with diameters of 1.5 mm, 2.0 mm, and 3.0
mm in a weight ratio of 1:1:1. A comparison of its grain size
distribution with that of Toyoura sand, which is widelyused in model experiments in Japan shows that theuniformity coefficient Uc is similar, with a mean diameter
D50 of around 2 mm, which is about 10 times that of
Toyoura sand. Furthermore, the unit weight of thealuminum rods model ground with this grain size
distribution is still within a relatively narrow range ofaround 21–22 kN/m3 even after changing the compaction
method and degree. Additionally, the grain size effectshould be noted in conditions where clear shear bands
tend to occur in the ground, such as in bearing capacity
View of Aluminum Rods
tests. This grain size effect is thought to occur because theFig. 4. Overview of aluminum rods model groundshear band thickness is proportional to the grain diameter.
For example, Toyosawa et al. reported from bearing
capacity tests in centrifuge model tests using dense river sand that the bearing capacity may increase due to the grain
size effect in cases where the breadth of footing B is less than 50 times the D50 value[5]. Using this as a reference, thenwhen conducting bearing capacity tests with a shallow foundation in this aluminum-rods model ground with these grain
size distributions, then the breadth of footing B should be at least 100 mm (approximately 50 times the D50 value).

The internal friction angle of the aluminum rods model ground is often easily estimated by an angle of repose test inwhich an aluminum rod is placed in a sample box and tilted, and the angle of repose obtained as the tilt angle at the timeof collapse is around 29–33°. Additionally, back calculation using the Rankine earth pressure equation from the passive
coefficient of earth pressure and active coefficient of earth pressure obtained from a retaining wall earth pressure
experiment conducted separately yielded an internal friction angle of 28–31°, which is about the same as the angle ofrepose[6]. Furthermore, back-calculation of the bearing capacity factor Nγ, and Nq from bearing capacity tests on the same
aluminum rods model ground also resulted in an internal friction angle in the range of 29-30 degrees.[7]Additionally, in model experiments using aluminum rods model ground, the ground materials themselves considerably
differ, making it difficult to determine a scaling factor of various physical quantities based on a strict similarity rule.
Therefore, the similarity rule in aluminum-rods model ground generally uses the idea that a dimensionless quantity (e.g.,bearing capacity factor Nγ, Nc, Nq, coefficient of earth pressure K) for the physical phenomenon to be reproduced is madeequal between the prototype and the model as needed.

3. Bearing capacity tests of scoured shallow foundation
We conducted vertical loading tests under conditions that artificially simulated the condition in which the ground at thebottom of the foundation was washed away by scouring in order to determine the relationship between scour depth andresidual bearing capacity exerted after a disaster [8],[9].
Fig. 5. shows a reproduction of scouring. The condition in which a hole is created by scouring on the upstream side of a6Volume 6, Issue 2

June 2024

bridge pier is reproduced by removing an aluminum rod, andthe scour depth d is used as the main parameter. After thescouring was simulated, vertical load was applied by using a
jack, and the relationship between the vertical load andsettlement was measured. Fig. 6 shows the results.
In Fig. 6, the settlement was set to zero before simulating
scouring (extracting aluminum rod). Additionally, the dead load
(65 N) was approximately 1/3 of the ultimate bearing capacity
under conditions where no scouring occurs. The displacement
when this dead load was applied represents the residual
displacement after a disaster. The results showed that theresidual displacement after a disaster increased with increasing
scour depth d.

Fig. 5. Modeling scour by removing aluminum rods

Meanwhile, as the loading continued, the load tended to increase from the vicinity of the residual displacement, showingthat the maximum load (i.e., residual bearing capacity after disaster) increased to about the same level as in the casewith no scouring. In other words, even if scouring caused damage that induced residual displacement, the expected
residual bearing capacity itself after the disaster may not decrease by much. This is consistent with the actual cases of
emergency restoration shown in Figs. 1–3, where the residual bearing capacity needed for train operation could be
expected without reinforcing the foundation.
300

After disaster250

Before disaster

Load (N)

200
150
100

Dead load (65 N)

50
0

0

2

4

6

8

Residual settlement(d=32mm)
d=0mm

d=13mm

10

12

14

16

18

20

10% of the foundation width (10 mm)

Settlement (mm)d=19mmd=26mm22

d=32mmFig. 6. Load-settlement curves after scour
4. Bearing capacity test of shallow foundation reinforced with press-in sheet piles
The restoration of foundations damaged by scouring (or preventative reinforcement prior to the disaster) requires workin rivers, so construction methods that do not use cement or concrete (or use only a small amount) are advantageous forwater quality conservation, and the use of press-in construction methods is expected. Sheet pile foundations thatcombine sheet piles and footings have previously been developed[10],[11],[12], and they are also used to reinforce river
bridge piers[1]. In general, sheet piles and footings should be rigidly connected and integrated in order to obtain highreinforcement effect with less material. However, in the case of reinforcement for scoured foundations in the river,construction efficiency and economy can be improved by eliminating the construction period, cost, and space requiredfor integrating the existing footing with the additional sheet pile. Therefore, an experiment was conducted to confirm thereinforcement effect when integration with the existing footing was omitted (however, the heads of the added sheet piles
were connected)[13].
Fig. 7 shows the experimental setup. A sheet pile model (aluminum plate) was installed around the footing with a breadthof footing B = 100 mm, and a vertical load was applied. The sheet piles and footing were not connected, but the sheet
piles on both sides were connected at the head. The main experimental parameter was the penetration length L of the
sheet pile model.
7Volume 6, Issue 2

June 2024

Fig. 7. Experimental setup for confirming reinforcement effect by sheet piles

Fig. 8 shows the load-displacement relationship fromunreinforced cases (Case L0) to cases reinforced withsheet piles with penetration length L = 20–140 mm(0.2–1.4 times the breadth of footing B) (Case L20–Case
L140). It can be confirmed in the figure that the bearing
capacity increases due to penetration.
Fig. 9 shows the relationship between penetration
length L and ultimate bearing capacity (maximum
vertical load up to 10 mm settlement). The results
confirmed that the reinforcement effect is notproportional to penetration length L but rather changes
in a step-wise manner with 0.8 times the breadth offooting B (L = 80 mm) as the boundary.
Fig. 8. Load-settlement curves (effect of penetration length L)

5. Conclusion
The press-in construction method is very much suitedfor post-disaster restoration and preliminary
reinforcement work for river bridge pier foundations,where there is increasing risk of scouring damage, butthere is still insufficient accuracy of evaluating themechanical performance before and after
reinforcement. In this article, we introduced
experimental examples of residual bearing capacity
immediately after a disaster and the effects ofadvance reinforcement. Evaluations are currently
limited to those that are independent from eachother, but in the future, we plan to conduct combined
evaluations as well as consider seismic performanceafter reinforcement. We hope to continue these
examinations and establish a logical evaluation anddesign method to contribute toward the realization ofa safe and more secure society.

Fig. 9. Relationship between L and ultimate bearing capacity8Volume 6, Issue 2

June 2024

Acknowledgements
The author expresses sincere gratitude to the following graduate students of Chuo University who performed the model
tests shown in this article: Ms. Yuna Sasaki, Ms. Moeka Hirano, and Mr. Ryuto Shikakura. And some part of this work was
supported by the JSPS KAKENHI Grant-in-aid for Scientific Research (c) (Grant Number JP20K04687).

References[1] Kuroki, Y., Nishioka, H., Kumabe, K. and Koda, M. (2018): Reinforcement of Damaged Bridge Pier by Scouring Using
Steel Pipe Piles, Proc. of the First Int. Conf. on Press-in Engineering 2018, Kochi, pp.549-554.
https://www.press-in.org/ja/publication/freefile/86/180[2] Nishioka, H., Shinoda, M., Sumi, Y. and Yamate, H. (2013): The Vertical Loading Test and Train Running Test to theBridge Pier of Spread Foundation which was Damaged by Scouring Settlement, 48th Japan National Conference on
Geotechnical Engineering, pp.203-204. (in Japanese)[3] Matsuoka, H. (1974): A Microscopic Study on Shear Mechanism of Granular Materials, Soils and Foundations, Vol.14,
Issue 1, pp.29-43. https://www.jstage.jst.go.jp/article/sandf1972/14/1/14_1_29/_article/-char/en[4] Kikumoto, M., Nakai, T., Zhang, F. and Shahin, H. (2008): Two Dimensional Model Tests Using Aluminum Rods Mass,
The Japanese Geotechnical Society, Geotechnical engineering magazine, Vol.56, Issue 10, pp.12-15. (in Japanese)[5] Toyosawa, Y., Itoh, K., Kikkawa, N., Yang, J.-J., and Liu F. (2013): Influence of model footing diameter and embedded
depth on particle size effect in centrifugal bearing capacity tests. Soils and Foundations, Vol.53, Issue 2, pp.349-356.
https://doi.org/10.1016/j.sandf.2012.11.027[6] Nishioka, H., Matsumoto, N., Fukuda, F., and Ono, K. (2022): Model excavation tests simulating the collapse of highbending rigidity cantilever-type earth retaining walls and proposal of a simple calculating method for the reasonableembedding length, Japanese Geotechnical Journal, Vol. 17, Issue 3, pp. 401-420. (in Japanese)
https://doi.org/10.3208/jgs.17.401[7] Yoshida, H., Isobe, Y., and Nishioka, H (2023): Assessing Residual Settlement in Column Foundations After an
Earthquake Using Horizontal Loading Model Tests, Proc. of 13th Int. Conf. on Geotechnique, Construction Materials& Environment, Mie, pp. 334-338.
[8] Sasaki, Y., and Nishioka, H. (2022): Vertical Loading Tests on Local Scoured Spread Foundation on Aluminum Rods
Model Ground, Int. J. of GEOMATE, Vol.23, No.98, pp.17–23.
https://geomatejournal.com/geomate/article/view/1472[9] Hirano, M., Sasaki, Y., and Nishioka, H. (2023): Evaluation of the bearing capacity of scoured bridge foundations usingaluminum rod ground model tests, Abstract Proc. of the 2nd Int. Conf. on Construction Resources forEnvironmentally Sustainable Technologies, Fukuoka, pp.55-58.
[10] Nishioka, H. (2017) Case-history Development of Sheet Pile Foundation, IPA Newsletter, Vol.2, Issue 4, pp.13-16.
https://www.press-in.org/_upload/files/Newsletter/Newsletter%20vol.2%2C4.pdf[11] Nishioka, H., Koda, M., Hirao J. and Higuchi S. (2008): Development of Sheet-Pile Foundation that Combines Footingwith Sheet Piles, Quarterly Report of RTRI, Vol.49, Issue 2, pp. 73-78. https://doi.org/10.2219/rtriqr.49.73[12] Nishioka, H., Koda, M., Hirao, J. and Higuchi, S. (2010): Vertical and combined loading tests for sheet pile foundation.
Int. J. of Physical Modelling in Geotechnics 10: 25-34, 2010. https://doi.org/10.1680/ijpmg.2010.10.2.25[13] Shikakura, R., Nishioka, H., Yamakuri, Y., Arai, Y. and Hirano, M. (2024): Experimental study on the influence ofpenetration length and eccentricity on the bearing capacity of sheet pile foundations, Proc. of the 3rd Int. Conf. on
Press-in Engineering, Singapore. (in press)

9

Volume 9, Issue 2

June 2024

Directors’ research and development activities

Performance of winged monopile in calcareous sand ground
Vu Anh Tuan
Associate Professor, Civil Engineering Department
Le Quy Don Technical University, Hanoi, Vietnam

Abstract
This study aims to investigate the behaviors of winged monopiles subjected to cyclic loading in a calcareous sand throughnumerical analysis. Axial load tests (push-in or pull-out) of monopiles with and without wings in a calcareous ground are
simulated using a three-dimensional finite element software, PLAXIS 3D. Prior to these simulations, triaxial tests on a
calcareous sand sampled from Vietnam were carried out to investigate the mechanism behaviors of the calcareous sand,aiding in the selection of an appropriate soil model and the evaluation of the corresponding soil parameters. The
hypoplastic model was adopted to simulate the sand. Interface elements were employed to simulate the slippage
between the pile shaft and the soil. The analyzed results show that the resistance of the winged pile is considerably higher
than that of the pile without wings.
1. Introduction
In the sea areas of Southeast Asia, especially around Truong Sa Island in Vietnam, calcareous sand is quite commonly
distributed. A problematic feature of the calcareous sand is high crushability of soil particles when subjected to highconfining pressure, shear stress, and cyclic loading. A monopile foundation is usually used for supporting offshore
structures subjected to cyclic loading caused by sea waves and/or winds as well as to vertical loading. To improve theshaft resistance, the use of a winged monopile, where reinforcement wings are implemented along the outer surface ofthe pile, is a feasible solution.
The physical and mechanical characteristics of calcareous sands have been summarized in [1, 2]. In a natural state,calcareous sediments behave differently from terrestrial silica sands, the most significant distinguishing feature being
their tendency to exhibit volume reduction upon shearing, even at relatively low normal stresses. It was pointed out in[2] that the tendency for volume reduction due to shearing plays a dominant role in the foundations of calcareous
sediments. A numerical study was conducted on the behavior of a single pile subjected to cyclic loading in the coral sand[3]. Al-Douri and Poulos [4] compared the predicted and observed performance of cyclic load tests on small-scale single
piles jacked into dry calcareous sand to study the accumulation of permanent displacement of the piles.
This study investigates the behavior of winged monopile subjected to cyclic loading in calcareous ground throughnumerical analysis. In the analyses, axial load tests (push-in or pull-out) of monopiles with and without wings in a
calcareous ground are simulated using a three-dimensional finite element program, PLAXIS 3D [5]. Triaxial tests on a
calcareous ground sampled in Vietnam are carried out prior to the analyses of the load tests to investigate the mechanicalbehavior of the calcareous ground and to select an appropriate soil model as well as to evaluate the corresponding soil
parameters. In this study, the hypoplastic model [6] is used to model the ground. Interface elements are employed tosimulate the slippage between the pile shaft and the soil. The analyzed results show that the resistance of the winged
pile is considerably higher than that of the pile without wings.
2. Triaxial Tests of The Calcareous Sand and FEM Simulation
The calcareous sand collected from Truong Sa Island in Vietnam was used in this study. Only soil particles having a particle
diameter, d, smaller than 4.75 mm were used in the experiments. Triaxial monotonic and cyclic CD compression tests on
calcareous sand with a relative density, Dr, of 70% were conducted at a confining pressure, p0, of 150 kPa. Cylindrical
specimens with a height of 100 mm and a diameter of 50 mm were used in the tests.
Fig. 1 and 2 show the experimental and simulation results of the triaxial tests for monotonic and cyclic loading,respectively. The experimental results indicate that post-peak softening behavior is observed, and dilatancy decreases
with increasing axial strain. Specifically, in the case of cyclic loading (Fig. 2a), the accumulative strain increases with thenumber of loading cycles.
Simulations of the triaxial tests were carried out to select an appropriate soil model and to evaluate the soil parameters.
In this study, soil models such as Mohr-Coulomb (MC), Hardening Soil (HS) [7] and Hypoplastic (HP) were used for the10Volume 9, Issue 2

June 2024

simulations. The FEM simulations results of the triaxial tests are also shown in Fig. 1 and 2. It is evident that MC and HS
models cannot simulate the post-peak softening behavior (Figs. 1a and 2a) and the reduction of dilatancy (Figs. 1b and2b) with increasing axial strain, εa. In particular, the MC and HS models are unable to simulate the accumulative strain
due to cyclic loading (see Fig. 2b). Meanwhile, the HP model [6] generally simulated the measured q vs. εa of thecalcareous sand well, both qualitatively and quantitatively, although there are differences in dilatancy curves between
the experiments and the simulations. The hypoplastic model will be employed for model ground in numerical analyses ofmonopiles, which are presented in Section 3.

Volumetric strain, εvol (%)

Deviatoric stress, q (kPa)

1200
1000
800
600
400
200
0
0

mono load
p0= 150 kPa

2

4

6

8

Experiment
FEM_HP
FEM_HS
FEM_MC10 12 14 16 18 20

Axial strain, εa (%)

-7
-6
-5
-4
-3
-2
-1
0
1
2
3
0

Experiment
FEM_HP
FEM_HS
FEM_MC2

4

6

mono load
p0= 150 kPa

8

10 12 14 16 18 20

Axial strain, εa (%)(1b) Volumetric strain εvol versus axial strain εa(1a) Deviatoric stress q versus axial strain εa

1200

Volumetric strain, εvol (%)

Deviatoric stress, q (kPa)

Fig. 1. The experimental and simulation results of the triaxial tests for monotonic loading.

1000
800
600
400
200
0
0

cyclic load
p0=150 kPa

2

4

6

8

Experiment
FEM_HP
FEM_HS
FEM_MC10 12 14 16 18 20

Axial strain, εa (%)(1a) Deviatoric stress q versus axial strain εa

-7
-6
-5
-4
-3
-2
-1
0
1
2
3
0

Experiment cyclic load
p0=150 kPa
FEM_HP
FEM_HS
FEM_MC24

6

8

10 12 14 16 18 20

Axial strain, εa (%)(1b) Volumetric strain εvol versus axial strain εaFig. 2. The experimental and simulation results of the triaxial tests for cyclic loading.
3. Numerical Analysis of Monopiles in Calcareous Sand
3.1. Description of Numerical Model
Case studies considered in this paper are close-ended monopiles with and without wings, subjected to vertical loading(push-in or pull-out loading) in calcareous sand ground. The monopiles made of steel have a total length of 25 m, with 24
m embedded and 1 m free-standing. They have an outer diameter of 1 m and a pile wall thickness of 0.015 m. The

11

Volume 9, Issue 2

June 2024

reinforcement wings of the winged pile have a width of 0.5 m (0.5D), with an opening angle of 120 degrees and a thicknessof 0.01 m. The wings are spaced at 1 m interval, as shown in Fig. 3.
Model ground in this numerical study consists of calcareous sand, with properties presented in the Section 2.
Groundwater influences the initial effective stress conditions, although for simplicity, a fully-drained condition was
assumed during loading, resulting in uncoupled analyses. Fig. 4 shows the dimensions of the model ground. The sideboundary extends laterally to 6 m (6D, D is the pile diameter) from the pile axis with restrained (fixed) horizontal
displacements applied. The base boundary, located 10 m (10D) from the pile tip, has restrained vertical and horizontal
displacements applied.
To model the pile, a hybrid model was used, consisting of a beam element surrounded by solid elements, according toKimura and Zhang [8]. In the hybrid model of this paper, beam element carried a large proportion of the axial stiffness,
EA, and bending stiffness, EI of the pile.
Interface elements were assigned along the pile shaft to simulate the slippage between the pile and the ground. An
innterface cohesion of 1 kN/m2 and an interface angle of 32 degrees were assumed, based on the triaxial test results andthe strength interface reduction factor of 0.67.

Fig 4. Dimensions of the model ground.

Fig 3. Dimensions of reinforcement wings.
3.2. Numerical Results and Discussions

Fig. 5 shows the analyzed results for the monopiles (with and without wings) subjected to push-in loading including
monotonic and cyclic load. Clearly, the winged-pile shows much greater resistance than the pile without wings underboth monotonic and cyclic loading. Firstly, consider the load-settlement curves of the pile without wings. It is interesting
to notice the difference in the pile resistance, which is influenced by loading types. The resistance of the pile after thecyclic loading decreases compared with that of the monotonic loading. Meanwhile, in the case of winged-pile, the pile
resistance is almost the same between the monotonic and cyclic loading cases.
Fig. 6 shows the load-displacement curves of the piles in the case pull-out loading, in which the pile resistance iscontributed by only the pile shaft resistance. Clearly, the resistance of the wing-pile is much greater than that of the pile
without wings. As for the single pile without wings, the shaft resistance attained to the ultimate value of around 2300 kN
after the pile head displacement reached about 0.01 m (w/D = 0.01). Meanwhile, the resistance of the winged pileincreased with the increase of the pile head displacement and attained a stable behavior even until the displacement
reached 0.1 m (w/D= 0.1). The resistance of the winged pile at w/D = 0.1 is 17000 kN which is over 7 times larger thanthat of the pile without wings, indicating a significant effect of the reinforcement wings on the pile shaft resistance. Note12

Volume 9, Issue 2

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0.00

0Pile head push-in load, Phead (kN)

0.02
0.04

5000 10000 15000 20000 25000 30000
Push-in test
Mono_No wings
Mono_wings
Cyclic_No wings
Cyclic_wings

0.06
0.08
0.10

18000

Pile head pull-out load, Phead (kN)

Pile head downward disp., whead (m)here that the resistance of a pile at w/D = 0.1 is considered as the pile capacity in design specification of many countries.
The differences in pile resistance between monotonic and cyclic loading are insignificant.

16000
14000
12000

Pull-out test
Mono_No wings
Mono_Wings
Cyclic_No wings
Cyclic_Wings

10000

Fig 5. Load-displacement curves in push-in test.

8000
6000
4000
2000
0
0.00

0.02

0.04

0.06

0.08

Pile head upward disp., whead (m)0.10

Fig 6. Load-displacement curves in pull-out test.

4. Conclusion
In this study, triaxial tests of a calcareous sand sampled from Truong Sa Island of Vietnam were conducted to investigate
the mechanism behaviors under monotonic and cyclic loading. After that, numerical simulations of the triaxial tests werecarried out to select an appropriate soil model and evaluate the corresponding parameters for numerical analyses on
behaviors of monopiles in the calcareous sand ground.
The results from both experimental and simulation of triaxial tests indicate that the Hypoplastic soil model is moresuitable than the Mohr-Coulomb or Hardening soil models for simulating calcareous sand, particularly under cyclicloading.
The numerical results show that the winged pile has considerably greater resistance than the normal pile without wings,
both in pull-out and push-in loading tests, indicating its high performance efficiency of the winged pile. However, in thisnumerical study, the pile installation effect was not considered. Consequently, conducting experiments through smallscale models and/or full-scale models, wherein the pile installation effect is considered, are necessary to evaluate theperformance efficiency of the winged pile in practical applications.
References
1. Murff, J.D. Pile capacity in calcareous sands; State of the art. Journal of Geotechnical Engineering, 113(5), 490-570 (1987).
2. Poulos, H.G. The mechanics of calcareous sediments. Australian Geomechanics, 8-41 (1988).
3. Kusumaningsih, D.A., Vu, A.T. and Matsumoto, T. Numerical study on behaviour of single piles in a coral sand. Proc. Soft
Soils 2016 Conf., Bandung, pp. D1-1 to D1-6 (2016).
4. Al-Douri, H.A. and Poulos, H.G. Predicted and observed cyclic performance of piles in calcareous sand. Journal of
Geotechnical Engineering, 121(1), 1-16 (1995).
5. Vu, AT., Matsumoto, T. Numerical Analysis on Behaviors of Winged Monopile Subjected to Cyclic Loading in a Calcareous
Ground. Lecture Notes in Civil Engineering, 18, 217-223 (2019).
6. Wolffersdorff, P.A. A hypoplastic relation for granular materials with a predefined limit state surface. Mechanics ofcohesive-frictional materials 1, 251-271 (1996).
7. Schanz, T., Vermeer P.A. and Bonnier, P.G. The hardening soil model: formulation and verification. In: Brinkgreve RBJ,
editor. Beyond 2000 in computational geotechnics. Rotterdam: Balkema, 281-290 (1999).
8. Kimura, M. and Zhang F. Seismic evaluations of pile foundations with three different methods based on threedimensional elasto-plastic finite element analysis. Soils and Foundations. 40(5), 113-132 (2000).

13Volume 9, Issue 2

June 2024

ReportOrdinary General Assembly 2024

The IPA Ordinary General Assembly 2024 was held from 13 to 24 May, 2024. The total votes have achieved the quorum
and all the presented Agendas were resolved in accordance with Article 22 of Constitution.
・Period:13 to 24 May 2024

・

Meeting place:

IPA Website (On-line voting through the Members Site)・

Agendas:https://www.press-in.org/en/page/general_assemblies

・

Number of eligible members:

719 (Individual Members: 671, Corporate Members: 48)

・

Quorum:360 (a majority of members）

・

Total votes：

452 ［achieved quorum］ (Turnout 63%）

Votes on each Agenda：
AgendasAgenda 1
Agenda 2

Affirmative votes

Dissenting votes

Results452

0

Approved451

1

Approved

Activity Report for FY 2023
Income and Expenditure
Statement for FY 2023

Agenda 3

Activity plan for FY 2024452

0

Approved

Agenda 4

Budget for FY 2024452

0

Approved452

0

Approved452

0

Approved

Agenda 5
Agenda 6

Election of the Directors andAuditors (2024-2025)
Amendments to Constitution

The list below shows the incoming and outgoing members of IPA Directors. Thanks to the outgoing directors for theirgreat contributions during the terms and very welcome the new directors.

Incoming Directors:

Director

David, Ko-Wei Lin

Director

Marawan M. Shahien

Director

Cristina de Hollanda Cavalcanti Tsuha

President & Representative Director
Chuen-Chang Enterprise Co., Ltd.
TaiwanProfessor
Tanta University Geotechnical Engineering Consultant
Egypt
Professor
University of São Paulo
Brazil14

Volume 9, Issue 2

Outgoing Directors:
Director

Director

Masaaki Terashi
Technical Advisor
GIKEN LTD.
Japan

Lei Yang
Vice President
SHANGHAI TUNNEL ENGINEERING
CO., LTD.
China

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June 2024

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June 2024

Event Report
iconNECt Seminar on Introduction of a Green Approach forPreventing Landslides in the Philippines, 1 December 2023
Mark Albert H. Zarco
Professor, University of the Philippines, Diliman

The National Engineering Center of the University of the Philippines Diliman in partnership with Daisho Company
Limited and the Department of Public Works and Highway (DPWH)of the Republic of the Philippines hosted throughits i-conNECt program and, organized a seminar entitled Introduction of a Green Approach for Preventing Shallow
Landslides in the Philippines last 1 December 2023. The seminar was offered to the public for free in partnershipwith Daisho Company Limited. Opening remarks were given by representatives from the DPWH Regional Office for
the Cordillera Administrative Region.
Resource speakers included IPA Directors Prof. Tatsunori Matsumoto and Prof. Mark Albert Zarco, together with Dr.
Shota Yoshida of Daisho Co. Ltd, and Dr. Xiong Xi of Kanazawa University. Also, in attendance were Mr. Jiro Oshima,
Senior Representative, Japan International Cooperation Agency (JICA) Philippines Office, and Mr. Ryuichi Hara, JICE
Technical Expert. The seminar was attended by more than 90 representatives from government, academe, andprivate sector. The event was covered by the Daily Manila Shimbun. During the seminar, updates on a demonstration
project in the Cordillera Administrative Region funded by JICA and implemented by Daisho Co. Ltd together with
the Department of Public Works and Highway were presented.
Prof. Zarco spoke about Llandslides in the Philippines. Mr. Hara talked about slope disaster mitigation projectprovided by JICA in the Philippines. Mr. Paragas of talked about Rockfall Slope Protection Systems. Dr. Yoshidapresented a slope reinforcement technology that does not require cutting trees. Prof. Emeritus Matsumoto lectured
on the behavior of the slope ground during heavy rains. Ms. Mimu Yoshida and Ryoei Kusumoto presented on theuse of 3D data in slope disaster prevention.
The i-conNECt series of seminars/webinars aims to disseminate information and provide a venue for discussion
among the industry, academe and the government on important issues affecting the nation. It aims to spreadawareness about relevant topics in engineering and how they affect the lives of ordinary people.

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Photo 1. Resource Speakers pose for a picture at the end of the seminar on Introduction of a Green Approach forPreventing Shallow Landslides in the Philippines held last 1 December 2023 at the National Engineering Center, Universityof the Philippines Diliman, Quezon City, Philippines.

Photo 2. Open forum during seminar on Introduction of a Green Approach for Preventing Shallow Landslides in thePhilippines last 1 December 2023.

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Volume 9, Issue 2

June 2024

Young Members Column

Determination of Peat Thickness in North Ayer Hitam State
Forest Reserve, Muar, Johor by Using Non-Destructive
Testing (NDT) for mitigation of peatland forest fire
Muhamad Firdaurs bin Abdullah
PhD Student, Faculty of Civil Engineering and Built Environment
Universiti Tun Hussein Onn Malaysia (UTHM)
I’m Muhamad Firdaurs bin Abdullah, a PhD student of Faculty of Civil Engineering and
Built Environment, Universiti Tun Hussein Onn Malaysia (UTHM). I have completed my
Master’s degree in Civil Engineering from UTHM back in 2017. As a graduate student
researcher, the author worked under Dr. Nor Azizi Yusoff on a variety of research
assignments. I was involved in research projects headed by Dr. Azizi such as green roof
thermal performance, soil-roots reinforcement, vertical garden, compact soil extruder,silent piling technology and visiting many geotechnical project sites. Throughout mygraduated study, the author has co-authored five papers in areas of Soil Bio- and Ecoengineering.

Currently, I am working on the project for water sustainability for peatland in North Ayer Hitam State Forest Reserve Muar,
Johor, Malaysia. This project is funded by National Conservation Trust Fund for Natural Resources (NCTF), under the
Ministry of Natural Resources and Environmental Sustainability. Malaysia contains about 3 million hectares peatland
which cover 8% of its total land. The depth of peat varies depending on the area. It helps to maintain water levels, acts
as a flood control and water supply system for communities as well as downstream ecosystem. The study is aimed todetermine the thickness of peat in Ayer Hitam Utara Forest Reserve, Muar, Johor by using a Non-Destructive Testing (NDT).
The survey data on peat thickness was collected at 10 sites located inside the forest. The resistivity data consisted of sixline wenner-schlumberger short arrays and were recorded in-situ using SAS 4000 ABEM Lund Imaging System, together
with a relay switching unit (Electrode Selector ES 10-64), two multiconductor cables, steel rod electrodes and jumpers.
The data, namely electrode spacing, depth of investigation, sub-surface resistivity, type of material and horizontal data
coverage was used to assess the thickness of peat. The recorded data were then processed using RES2DINV software toobtain 2-D inversion model of the sub-surface. The data were also equipped with ten models of inverse resistivity section
for all sites showed a varies thickness of peat in range between 5 to 15 m. The data obtained can be used by thegovernment and stakeholders for peatland fire prevention program to mitigate haze in Malaysia and conservation of Ayer
Hitam Utara reserve forest. The application of silent piling technology might be useful in order to sustain the waterbalance of the forest reserve by retaining huge amount of water from leaving the forest at fast rate. Thus, the preventionof peatland forest fire can be made more effectively.

Fig. 1. Resistivity line survey conducted of few locations inside North Ayer Hitam State Forest Reserve, Muar, Johor

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Volume 9, Issue 2

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Fig. 2. Output image processed using RES2DINV software to obtain 2-D inversion model of the sub-surface of peatland

Fig. 3. An expedition by UTHM team to assess depth of peat in the forest (left) and the peat sampling made using a peat
sampler during the expedition (right)

19

Volume 9, Issue 2

June 2024

Event Diary
Title

Date

Venue

■ IPA Events

https://www.press-in.org/en/event

The Third International Conference on Press-in
Engineering (ICPE 2024)

3-5 July 2024

Singapore■ International Society for Soil Mechanics and Geotechnical Engineering
http://www.issmge.org/events

7Th International Conference on Geotechnical andGeophysical Site Characterization

18-21 June 2024

28TH EUROPEAN YOUNG GEOTECHNICAL ENGINEERS
CONFERENCE 2024

25-29 June 2024

5th International Conference on Environmental
Geotechnology, Recycled Waste Materials andSustainable Engineering

4-6 July 2024

Warsaw, Poland

14th International Symposium on Landslides 20247-12 July 2024

Chambery, France

The 6th International Conference on GeotechnicalEngineering

21-23 July 2024

Semarang, Indonesia

XVIII European Conference on Soil Mechanics andGeotechnical Engineering

25-30 August 2024

Lisbon, Portugal

4th International Conference of International Society
for Intelligent Construction (ISIC 2024)

10-12 September 2024

Orlando, Florida

77th Canadian Geotechnical Conference and the 16th
Joint CGS/IAH-CNC Groundwater Conference

15-18 September 2024

Montreal, Canada

Nordic Geotechnical Meeting - NGM 2024

18-20 September 2024

Göteborg, Sweden

IS-Grenoble 2024: International Symposium on
Geomechanics from Micro to Macro

23-28 September 2024

Grenoble, France

DFI S3: Slopes, Support and Stabilization

6-8 August 2024

Aurora, Colorado

DFI-India 2024: 13th Annual Conference

19-21 September 2024

Panaji, Goa, India

Barcelona, Spain
Demir Kapija, North
Macedonia■ Deep Foundations Institutehttps://www.dfi.org/events/

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June 2024

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22June 2024

Volume 9, Issue 2

June 2024

Editorial Remarks from persons in charge
Welcome to the IPA Newsletter, Volume 9, Issue 2. Thank you for giving me an opportunity to work in the editorial groupfor this issue. On behalf of the persons in charge, I wish to express my appreciation to the authors and the secretariat for
their outstanding contributions to this issue.
As Message from the President, Prof. Chun Fai Leung introduces about the 3rd International Press-in Conference whichis coming on 3-5 July 2024. The theme of this international conference is 'Superiority of press-in piling towards sustainable
construction in tackling climate change for infrastructure development.' We look forward to your participation at theconference (https://2024.icpe-ipa.org).
This Newsletter issue has presented a number of interested articles on the bearing capacity problem. It also introduces ause of the press-in technology for post-disaster restoration and preliminary reinforcement work for river bridge pierfoundation. Also included in this issue is a report on recently held international semiar on Introduction of a Green
Approach for Preventing Landsliides in the Philippines held last December 2023 in Philippines.
We wish you all the best, and thank you for reading the newsletter.

Pastsakorn KitiyodomMichael Doubrovsky

23

Adnan Anwar Malik