bluuebunny/crossref_metadata_2025_split huggingface dataset:
Simulation of temperature and chemical weathering effect on marble rocks
Authors: Vagnon F , Costanzo D , Ferrero A M , Migliazza MR , Pastero L , Umili G 
Published: September 2021

Abstract
Physical and mechanical properties of building stones can vary due to different degradation mechanisms caused by temperature and chemical agents. The problem of chemical and thermal weathering on marble rocks is an important issue to consider for designing building façades since it may cause sugaring, bowing, cracking and spalling. Moreover, an accurate comprehension of induced damages is required for restoration and conservation of heritage monument purposes. While thermal weathering has been widely studied in the last years, the combined effect of thermal and chemical weathering (that here is intended as the combined action of rainwater and atmospheric pollutants) is still poorly understood. In this study, no-destructive (ultrasonic pulse velocities) and destructive tests (bending tests) were performed on Carrara marble slabs in natural and after thermal (with target temperatures respectively of 50 and 90°C) and thermo-chemical treatment. Thermo-chemical treatments were performed by soaking the specimens in a 5×l0−6 mol/l solution of sulphuric acid at pH=5 to simulate the acid rain behavior, at constant target temperatures, for one week. In general, for each weathering mechanism, progressive degradation of the physical and mechanical properties of marble specimens was observed. In particular, a marked drop in flexural strength, mirrored by a wide variation in P- and S-wave velocity, was found in specimens chemically treated at target temperature equal to 90 °C.
Investigations and stability analysis of San Marcellino cavities in the historical centre of Naples
Authors: Fasano G , Allocca V , Bilotta E , Nicotera M V , Ramondini M , Russo G , Russo M , Calcaterra D 
Published: September 2021

Abstract
The historical centre of the city of Naples is characterised by a network of underground anthropogenic cavities. Most of these cavities are stable and safe but sometimes for several reasons they are at least partially responsible of the occurrence of instability phenomena such as sinkholes and collapses. The opening of a sinkhole in the cloister of the Ancient Royal Boarding School (known as Educandato Reale of San Marcellino) led to fears of instability in the known underlying cavities. Therefore, a site investigation program was carried out to ascertain the causes of the event. The investigation concluded that the sinkhole was not related to the underneath cavities, located in tuff between 12 and 20 m beneath the main building. Nevertheless, due to the interest raised by the preliminary safety assessment, such a cavity system was selected within the MOSCAS project for further studies. The results of the site investigations and the stability of the cavities determined via FEM code Plaxis 2D are presented and discussed in this paper.
Investigation, design and mapping of Shaft O1 on Phase 2 of the Deep Tunnel Sewage System project in Singapore
Authors: Jack C D , Debroy P , Lyall R J W , Jinrong Y 
Published: September 2021

Abstract
The Public Utilities Board (PUB) of Singapore is currently progressing Phase 2 of the Deep Tunnel Sewage System (DTSS) project. Leighton Contractors Asia Limited (LCAL) have been awarded Contract T-09 of the project which runs approximately 8 km from the intersection of Clementi Road and the Ayer Rajah Expressway (AYE) to the intersection at Jurong Pier Road and AYE. LCAL have appointed COWI to act as their designer. Contract T-09 includes eight shafts, including Shaft O1 located between the Jurong River to the west and Penjuru Road to the east in the Jurong region of south-west Singapore. This paper discusses the rock engineering aspects of Shaft O1, including the engineering geological aspects and the methods of analysis used to design the reinforcement and support of the section of the shaft excavated in rock. Finally, the conditions encountered and the support installed during the engineering geological mapping of the shaft are described. The geology at Shaft O1 comprises made ground overlying Kallang Formation deposits and then weathered rocks of the Jurong Formation. Development of the ground model included several stages of desk study and ground investigation and ultimately six boreholes and eight probeholes were carried out at and around the shaft location. The analysis methods used included the Q-system, analytical closed-form calculations, use of the Unwedge software package, rock bolt and sprayed concrete design and a stand-up time assessment. The design was prepared during 2018-19 and the shaft was successfully constructed during 2019.
Rock characterisation for a road tunnel in Mumbai (India)
Authors: Battaglia D , Redaelli M 
Published: September 2021

Abstract
The Mumbai Coastal Road is a freeway currently being constructed along the western coast of Mumbai. A key element of this route is a twin-bore tunnel with total length of about 3km (a 2km TBM-excavated central section, plus cut-and-cover ramps at both ends). The tunnel alignment underpasses Malabar Hill and then runs under Chowpatty Beach for most of its length. The central section is located below the sea level with ground covers ranging from a maximum of 70m at Malabar Hill to less than 15m under Chowpatty Beach. Each bore, excavated by Tunnel Boring Machine (TBM), has an internal dimeter of 11m and includes a section with a horizontal radius of curvature tighter than 400m. This paper describes (i) the desk studies and the geological survey which provided the basis for an additional ground investigation plan, (ii) the results of the additional boreholes, in situ test and laboratory test, (iii) the overall characterisation of the rock mass (and of the overlying soils) based on the entire set of old and new data. The rock characterisation provided the fundamental information for the TBM type selection, and for the design of all the underground works. The launching chamber and the first part of the TBM drive are located within a Basaltic lava flow, while the second part of the alignment is set in Volcanic Breccia underlying the fine-grained soils and made ground of Chowpatty Beach.
EARTH RETAINING STRUCTURES THAT ALLOW ROAD INFRASTRUCTURE PROJECTS COASTING A FLYSCHIOID ROCK VALLEY
Authors: Mangiola A , Malgeri G D , Mittiga E 
Published: September 2021

Abstract
This note concerns the main geotechnical features of two road infrastructures, located in northwestern Italy. They are adjoining and situated from km 31+500 to km 35+600 of the national road “Strada Statale n. 45 di Val Trebbia”, along Trebbia river valley, across the Ligurian Apennines. The road, mostly in the half-way section, coasts a valley featured by orographic slopes with an average slope of 25°-30°, which rise up to 1100m above sea level. The stratigraphy, starting from the top level to the deepest, shows: a thin layer of eluvial-colluvial soil; a layer, 3-5m thick, of fractured rock, and underneath the hard marl substrate that belong to the flyschioid formation of Ronco. In this context, to widen the carriageway, improve the design speed of the road section and carry out the works under traffic, a systematic use of earth retaining structures has been conceived. Thanks to the experience taken from the works of the previous project, a more conservative geotechnical characterization has been adopted in the second one. This has meaning for the lithotype called intact rock, in the equivalent Mohr-Coulomb model, a significant reduction in cohesion against a slight increase of friction angle; furthermore, a correspondent variation resulted for the fractured rock.
Effect of rear walls on the rocking response of rock blocks under seismic excitations
Authors: Mennitti M , Maiorano R M S , Aversa S 
Published: September 2021

Abstract
The rocking response of rigid free standing bodies subjected to seismic excitation has been studied by many researchers interested in different slender elements such as ancient stone columns, tombstones, rigid building structures. The extension of this model to rock mechanics has been proposed by a few authors. The rocking response of rectangular free standing bodies subjected to horizontal accelerations of natural recorded motions showed that the pseudo-static approach, based on Peak Ground Acceleration (PGA), permits only the determination of the uplift conditions and the beginning of rocking. It does not permit to evaluate the overturning of the blocks. The combined effect of vertical and horizontal seismic motions is negligible and, in some cases, beneficial. This paper presents a new mechanical model, called “one-sided rocking”, that takes into account the presence of a rear rigid wall, that is a typical scenario for the rock blocks completely detached from the cliff but close to it. The dynamic response of a great number of rectangular rigid blocks, subjected to 62 recorded earthquake motions on rock soil (from US, Europe and Asia), has been analysed considering only the horizontal acceleration. The results show that the presence of the wall is detrimental for the rocking stability. However, there is still a safety reserve more significant for large blocks and rich frequency content time histories. This reserve could be taken into account in simplified (pseudo-static) analyses through reductive coefficient of PGA.
The assessment of possible deformations in the fault zone
Authors: Barykina O , Kalinin E , Zerkal O 
Published: September 2021

Abstract
One of the most relevant aspects for engineering geology regarding faults is the characterization of the changes induced by a fault and the assessment of possible fault movements. This zone cannot be clearly and well observed in field studies. However, it plays a negative role in the construction and operation of structures. In this zone, unfavorable phenomena, such as rock collapses, displacements, etc., may occur. The purpose of the present study is to estimate the size of fault changes, to reveal the peculiarities of stress distribution within the fault influence zone and to characterize free surface movements. The site of the Rogun HPP was chosen as the object of the study. Rogun HPP is located on Vakhsh River (Tajikistan) in a gorge of 400 - 500 m deep. The site of the dam, which will be about 350 m high, is located in a single tectonic block bounded by sub-parallel Ionakhsh and Gulizindan Regional Faults. The complex of Jurassic-Cretaceous sediments in this block lies monoclinically. According to the results of complex inclinometer-deformographic observations at the Rogun HPP site, the faults are tectonically active, with vertical displacements in 1-3 mm per year. In the scheme of numerical simulation, the width of the Ionakhsh Fault together with the crushing zone was taken as 20 m. For all rocks it was accepted: Young modulus – 3000 MPa; Poisson’s ratio - 0.3; density - 2.6 g/cm3. Horizontal compressive tectonic force was given as 12 MPa. The simulation showed that the dynamic influence zone is limited to 200 m on the side of the lying wing and 70 m on the side of the hanging wing, and the concentration zones are located at the mouth and in the middle part of the fault on the side of the lying wing and between the hanging side of the fault and the bottom of the valley. The analysis of the movements of eight points of the surface showed that the direction of movement corresponds to observed in nature. The total amplitude of vertical displacements of two points at the valley is 0.51 m. The values of the resulting displacements on the different sides of the fault are 0.22 and 0.49 m. According to geological data, the width of tectonic breccia zone of the Ionakhsh Fault is 120 m. However, according to numerical simulation the influence zone is about 270 m. Thus, the simulation showed that the size of real fault influence zone is more than twice as large as that measured in nature.
Rainfall-triggered debris flows: triggering-propagation modelling and application to an event in Southern Italy
Authors: Porta G La , Leonardi A , Pirulli M , Castelli F , Lentini V 
Published: September 2021

Abstract
Debris flows are high-speed and unpredictable phenomena, considered among the main sources of hazard worldwide, since they can affect structures, the economy, and human lives. Rainfall typically triggers these events, causing the flowing of the unconsolidated soil downslope. This work focuses on debris-flow events characterized by multiple triggering areas, which are extremely complex since they involve a spatial sequence of numerous triggers in a relatively small portion of the slope. Numerical modelling of this type of phenomenon can contribute to hazard and risk assessment, which is key to designing effective mitigation structures. In this article, two different models are applied for triggering and propagation, respectively. The former computes the transient pore-pressure changes and the consequent factor of safety variation caused by rainfall infiltration, inducing the triggering of the event. The latter is a depth-averaged numerical model that simulates the event runout, and whose parameters are calibrated through back-analysis. The applicability of the two combined approaches is tested through modelling of an historical event in Southern Italy, which was characterized by large mass releases from multiple triggering zones. Residential areas were hit, suffering serious consequences. Two rheologies are compared to individuate the most suitable propagation model for the study case and obtained results are commented.
Modelling the behaviour of a soft rock using a kinematic hardening constitutive model
Authors: Laera A , Rouainia M , Elia G 
Published: September 2021

Abstract
Soft rocks are of great geological and geotechnical interest, due to their mechanical and structural characteristics falling between those of a soil and those of a rock. This presents several challenges for constitutive and numerical modelling. Here we propose a calibration strategy of an advanced kinematic hardening model with structure degradation against experimental data on soft rocks, accounting for their features at the micro- and macro-scales. The experimental results show a highly structured material, with strength and stiffness being controlled by inter-granular bonding as well as by mean effective stress. The clay content of soft rock samples seems to be a dominant factor: the specimens show lower stiffness and strength when the content is higher. Accordingly, the samples have been classified into two different types (A and B). The constitutive model reproduces well both the mechanically strong and stiff behaviour of Type A as well as the more ductile mechanical response of Type B specimens observed during drained triaxial compression tests. With increasing confining pressures, the transition from brittle and dilatant to more ductile and contractant behaviour observed for both types of rocks is well captured by the adopted constitutive model.
Analysis of the techniques for assessing the features of blast-induced fragmentation in an open pit quarry
Authors: Cardu M , Calzamiglia A 
Published: September 2021

Abstract
The paper deals with the study of empirical models for the analysis of blasts-induced fragmentation. To verify the reliability of the method, the results obtained a priori through the application of the models are compared with the analyses of muck piles photos taken from a series of blasts in an open pit quarry, thanks to the Split-desktop software (Split Engineering, LLC, Tucson, USA). The study of the particle size distribution is very important when sizing an excavation site, as the average size of the pile must be compatible with the equipment used for clearing and conveyance, and with the first phase of the processing plant, i.e. primary crushing. After a description of the excavation technique in use at the quarry site, its main characteristics are outlined. The parameters used to create the empirical models refer to the geomechanical characteristics of the rock, the geometry of the blasts, the characteristics of the explosive and its interaction with the rock mass, paying attention to the correlation between initiation timing and induced fragmentation. A detailed description of some empirical models together with the Split-desktop software were therefore provided. Thanks to both data and photos of the muck-piles from the exploitation at the quarry, the particle size curves resulting from each model were compared with those obtained from the software. This allowed to validate the empirical method in a preliminary design phase.
Advancing of the geomechanical forecasting system and substantiation of mining at rockburst hazardous deposits
Authors: Semenova I E , Avetisian I M 
Published: September 2021

Abstract
The paper presents the main approaches and their advancing for the systems of rock mass stress-strain state forecasting during mining of adjacent rockburst hazardous deposits. Such systems based on the original Sigma GT software are used at several Russian mining companies which develop solid rock deposits, prone to brittle fracturing and undergoing the gravitational-tectonic stress-strain state. At that, the mining-induced impact on the rock mass is accompanied by occurrence of dynamic rock pressure. The geomechanical situation forecast systems have been applied directly at mining companies for more than 10 years and have shown their high efficiency. The efficiency is associated primarily with the operative calculation of stress-strain state in case of exacerbations of the geodynamic situation and the potential consideration of various mining options in order to reduce stress concentration and give recommendations for supporting and unloading measures in mine workings. In addition, the Sigma GT software is used in annual and long-term mining planning. Initially, such systems were developed for individual rockburst hazardous mining blocks, and their efficient operation time was limited to a 3-5 year period, that is, the block mining time. Further on, taking into account the needs of companies, the systems began to include a whole deposit or even several deposits. Being applied, the system is constantly developed and advanced and adapted to specific conditions and tasks. The most actual tasks are combination of the results of stress-strain state modeling with seismic monitoring data; creation of a hierarchical system of interconnected multiscale volume models; more complete consideration of structural heterogeneities of the rock mass and development of a recommendation block for safe mining operations, taking into account the geomechanical situation forecast data. The solution of these problems is considered on the example of a section of the Khibiny apatite arc, within which underground and open mining is carried out in the zone of mutual influence.
Evaluating the behaviour of stiff polymer-modified cementitious thin spray-on liners from small and large scale testing
Authors: Plessis M du 
Published: September 2021

Abstract
The application of permanent areal support is recognised as a measure to either retain or prevent the mobilization of potentially unstable keyblocks between installed support elements. Various areal support methods have been developed to provide support to the freshly exposed area created by the blast and to provide support between existing support elements. These methods consist of either shotcrete, thin spray-on liners (TSL), blast resistant mesh or temporary (removable) nets. This paper focuses on the application of polymer-modified cementitious TSLs which is the type predominantly applied in South-African underground mines. Significant amounts of research has been conducted on TSLs. The majority of the research consisted of predominantly laboratory testing. The results of the tests only provide an output which can be used to measure a specific characteristic (i.e. tensile strength) against other products. The output obtained from laboratory tests are not understood, cannot be benchmarked against good or poor performing products or quantitatively related to the performance of the product when applied in-situ on a large scale. This situation is problematic as different support suppliers make claims in terms of the performance of their products based on a material property or small scale testing. The behavioural mechanism of a rockmass supported by TSLs is not understood. It is therefore not clear what critical TSL parameters will affect rockmass stability. Very little work has been conducted locally to test the in-situ behaviour of TSLs once applied. An extensive testing program was developed to establish how the material properties of a TSL as tested in a laboratory would relate to small and large scale in-situ behaviour. This paper discusses the testing conducted and the high level findings.
Propagation analysis and risk assessment of an active complex landslide using a Monte Carlo statistical approach
Authors: Brezzi L , Carraro E , Gabrieli F , Dalla Santa G , Cola S , Galgaro A 
Published: September 2021

Abstract
The risk assessment of a rapid landslide is a difficult topic, even if based on the results of numerical analyses. The hypotheses on which every model is developed, the choice of rheological laws to be adopted, and the selection of soil parameters make the simulation results highly dependent on the user. This is particularly evident when there is no model calibration for the specific site or reliable information on soil properties. The paper presents a forecasting process obtained using a Monte Carlo approach in coupling with a propagation model developed with the SPH integration technique. The Monte Carlo analysis allows automatically carrying out a large number of simulations, each performed using an independent parameter set randomly selected within a priori assigned statistical distributions. The numerical results are then analysed with statistical tools to create a risk map based of the frequency of the unstable mass runouts. In this way, it is possible to reduce the user dependence of results and increase the examined potential scenarios. The procedure is here applied to the case study of the Sant’Andrea landslide, a slope movement active since several decades in the municipality of Perarolo di Cadore (Belluno, Italy). This complex slide involves an about 30 m-thick deposit of calcareous debris overlying anhydrite-gypsum rocks. Depending on the intensity and duration of rain, the slope alternates phases characterized by slow displacements and significant accelerations, then followed by a long relaxation period in which the displacement rate slowly regresses, without returning to the previous condition of movement. In recent years, the landslide activity has caused a progressive enlargement of the unstable area and a gradual increase of the basal rate, thus increasing the risk that the landslide may suddenly undergo to the collapse. Moving from the knowledge of the unstable volume, an SPH propagation model is used to study the area affected by the debris-flow runout. In particular, the analysis aims to define a statistical strategy to perform and interpret a large number of simulations and to create the consequent risk map. The analyses carried out lead to a satisfactory interpretation of the spatial variability of the deposit heights referred to the post-failure conditions, useful for the development of a risk analysis, from which a site risk map can be obtained.