bluuebunny/crossref_metadata_2025_split huggingface dataset:
Stability assessment of rock slopes combining Slope Mass Rating and Qslope classification systems: A case study in Cerro San Eduardo (Guayaquil, Ecuador)
Authors: Macías A M , Vera D K , Borja C P , Jordá-Bordehore L 
Published: September 2021

Abstract
In the present study, the stability of the slope located in the Modesto Apolo Ramírez Avenue, is analyzed. The avenue is located prior to the access to the Cerro San Eduardo tunnel, which has had habitual problems of falling blocks to the roadway. For the study, empirical methodology was applied, including the data mapping based on geomechanical classifications such as Rock Mass Rating (RMR), Slope Mass Rating (SMR) and Q-Slope index, which assign a defined score, obtaining the quality of the rocky mass, and with this, the degree of stability of the slope. In addition, through the application of RocFall software, the empirical methodology has been compared with the analysis of rockfall trajectory, making a retrospective study of behavior and simulating the constant falling of blocks on the roadway.
As a consequence of the exploration, it was evident that the geomechanical classifications-in this particular caseare not completely effective to determine the degree of stability of the massif. This is due to the fact that, even though the slopes are globally stable, these classifications do not seem to adequately determine a level of risk against rockfalls, as can be seen from visu. Therefore, it can be seen that the slope does not have a risk of collapse, but instead presents a high danger of landslides that could cause considerable economic and human lives losses. The study recommends geometric solutions for impact mitigation to prevent future damage.
Sustainable Shotcrete with Crushed Waste Glass
Authors: Serati M , Malgotra G , Jackson N , Basireddy SMR , Asche H 
Published: September 2021

Abstract
There is an ever-increasing amount of waste glass generated worldwide that is currently sent to landfill, and has a high potential for re-use. In Australia alone, the consumption of glass is 1.36 million tonnes, with the state of New South Wales producing the highest amount. Traditional landfilling and stockpiling of waste glass are not an environment-friendly solution, and the re-use of waste glass has become an important research topic in Australia and worldwide. This Project employs an experimental study to estimate waste glass re-cycling in shotcrete production. Mechanical strength and fracture properties of the new mix designs are compared against the controlled mixes at 0% waste glass inclusions. From the results, no impaired performance was recorded by substituting sand with crushed waste glass even at a high percentage ratio of up to 100%. While further research is needed, the promising early results highly encourage the applicability of crushed waste glass for sustainable shotcrete design, a topic that is yet relatively under-researched.
Solving the problems of exploitation safety of potassium salt deposit based on joint application of geophysical and geomechanical studies
Authors: Kashnikov Yu A , Shustov D V , Ermashov A O , Lebedeva O O , Zhukov A A , Prigara A M 
Published: September 2021

Abstract
The reliable determination of the physical and mechanical properties of the rock is one of the major issues of geomechanical modelling. It is needed to ensure exploitation safety in underground mine. This is especially relevant for the huge potassium salt deposits which uniqueness is the presence of the watered rocks that lies above the exploiting potassium seams. Particularly, a part of the rock mass that lies between potassium seams and watered rocks is called waterproof strata (WPS). The highest risk is the presence and propagation of the cracks in WPS through which the above-water can probably enter the openings that could lead to the total flooding of the mine. In order to prevent it and to provide exploitation safety the joint application of geophysical and geomechanical studies is suggested. In this paper 2D mine seismic investigations and geomechanical studies are described. And, as the conclusion, the analysis of the stress-stain state of the rock mass and its potential weak zones are presented.
Combining active and passive acoustic methods to image hydraulic fracture growth in laboratory experiments
Authors: Momeni Seyyedmaalek , Liu Dong , Lecampion Brice 
Published: September 2021

Abstract
We combine active and passive acoustic measurements to improve the spatio-temporal imaging of hydraulic fracture growth performed under true triaxial confinement in the laboratory. 64 active piezo-electric transducers (54 P waves, 10 S waves) work in source (32) - receivers (32) mode to perform an acoustic survey at repetitive intervals (every 10 seconds) during a hydraulic fracture growth experiment. The analysis of the evolution of the active acoustic monitoring changes allow to image the evolution of the fracture front (via an inversion of the active acoustic waves diffracted by the fracture front). An additional 16 piezoelectric transducers are pre-amplified and work in passive mode continuously recording at 10MHz. We present a nearly-automatic passive signal processing, acoustic emission detection, and location algorithm. This allows to record, detect and to locate acoustic emissions associated with fracture initiation and growth in between the active acoustic measurement sequences. Using a hydraulic fracturing test performed in gabbro, we discuss how active and passive acoustic monitoring complements one another and bring different type of information on hydraulic fracture growth.
A Thermo-elasto-plastic Evaluation of Stress State of Mars
Authors: Aydan Omer 
Published: September 2021

Abstract
There is recently an increasing interest to explore the ways to find out the characteristics of other planets and possibility of exploiting their mineral resources. The images sent to Earth from Mars exploration rovers showed that rocks and geological and tectonic structures are strikingly similar to those in Earth. In this study, the stress state of Mars is investigated using a spherical symmetric body concept together with the consideration of a thermo-elasto-plastic behaviour of the Earth’s constituting materials on the basis of the previous investigation of the stress state of Earth by Aydan [1,2,3]. Fundamentally four different situations, namely, fluid, elastic, elasto-plastic and thermo-elasto-plastic have been considered and the computational results are presented and their implications are discussed.
Construction works above cavities, investigation of an undermined area
Authors: Zenah J , Görög P 
Published: September 2021

Abstract
Construction work above previous mining area is always a great challenge from the engineering point of view. In the southern part of Budapest, the previous mining activities resulted more than a hundred thousands of square meters of cavities. These cellars cut into porous limestone with different depth, but mostly close to the surface; nowadays, these cellars are located inside a residential area, and some part of the undermined area is planned to build because this is an empty and valuable area. For the construction of these improvements, it is necessary to perform detailed investigations and stability calculations. This paper is introducing the detailed investigation process of a significant cellar which will be involved by construction activities. Three buildings are planned to build above it. The studied cellar located in the 22nd district of Budapest, Hungary, with a depth between 4.3 – 7.7 m, with a wide range of pillars’ width between 0.73 – 7.7 m according to the studied cross-sections. The investigation starts with geometrical measurements and core drillings to map the rock mechanical properties of the host rock. Several laboratory tests were done for obtaining rock mechanical parameters for modelling. After creating the geotechnical model, it was used for FEM calculations using RS2 software. Four cross-sections were chosen across the cellar system in different locations and various directions modelling the surface load of the planned building. The stability of the cellar was studied from two different viewpoints: firstly, the factor of safety was determined, and secondly, the settlement was calculated as an effect of the surface load. A displacement measurement system was set up in several cross-sections of the cellar to compare the calculated and real displacements in the future.
The numerical modeling of heterogeneities by the finite element method in 3D setting
Authors: Dmitriev S , Semenova I , Shestov A 
Published: September 2021

Abstract
The paper proposes a variant of the algorithm for 3D numerical simulation of the rock mass stress-strain state in the vicinity of structural heterogeneities by the finite element method. Modeling of the stress-strain state is used, among other things, when analyzing the fractures in the rock mass, which can occur as a breakage or a shear along the weakening planes. The rock massif has a block structure, where the boundaries of various-scale blocks are structural disturbances of different orders. The surface planes of structural heterogeneities usually have complex geometry and spatial orientation, so the most adequate results can be obtained by 3D modeling of the disturbed rock mass. Besides, it is important to take into account the type of the stress-strain state, which can be not only gravitational, but also gravitational-tectonic, including horizontal loading of the rock mass. Accounting these features allows obtaining the most adequate geomechanical model of the studied object. For this purpose, the authors have studied and analyzed the existing approaches to modeling heterogeneities in the rock mass, including using the Goodman contact element, and developed its 3D modification. A mining engineer needs to have a handy tool that allows creating and editing a geomechanical model, taking into account mining plans and related sections. The model navigation, edition of its individual blocks to specify geology and creation of local sub-models make it necessary to use structured meshes of finite elements. Modification of the model with the introduction of contact elements entails the creation of an unstructured mesh, which complicates further manipulations with it. To solve this problem, a special zero element was developed, which allows saving a structured mesh format when implementing a contact element. This zero element, like the contact element, has zero thickness, and its nodes have averaged strength characteristics of adjacent blocks of the undisturbed rock mass. The result of these studies is a tool that allows creating 3D models of the rock mass stress-strain state, taking into account its structural heterogeneities and preserving the regular structure of the finite element mesh.
Preliminary study on PFC3D microparameter calibration using optimization of an artificial neural network
Authors: Kim J , Choi J W , Song J J 
Published: September 2021

Abstract
Microparameter calibration for matching macroscopic responses of particle flow code 3D (PFC3D) models is generally conducted through trial-and-error which is inefficient and time-consuming. Several automatic calibration methods have been proposed but they are still limitations in the number of calibratable microparameters, range of macroscopic responses and degree of freedom in user-defined constraints. To overcome such limitations, a novel calibration method is proposed utilizing the constrained optimization of an artificial neural network (ANN). The ANN is trained with 600 PFC3D simulations to predict the unconfined compressive strength (UCS), Young’s modulus (E) and Poisson’s ratio (v) of a PFC3D model for a given set of 15 microparameter values. Unlike other ANN-based DEM calibration methods, the proposed method calibrates microparameters by optimizing the ANN inputs rather than obtaining the calibrated values as the ANN outputs. The integration of a PFC3D-mimicking ANN with constrained optimization enables microparameter calibration for a wider range of microparameters, macroscopic responses and a higher degree of freedom in user-defined constraints.
Piezoelectric effect does not contribute in thermal drilling of quartz bearing rocks
Authors: Saksala T 
Published: September 2021

Abstract
This paper presents a numerical study on a possible piezoelectric effect in thermal drilling of Quartz bearing rocks. For this end, the governing piezoelectro-thermo-mechanical problem is solved with the finite element method. The granitic rock material, consisting of Quartz, Feldspar and Biotite minerals, is taken as linear elastic but heterogeneous and anisotropic. Temperature dependence of material properties is neglected. The simulation demonstrates that the secondary stresses arising from converse piezoelectric effect are three orders of magnitude smaller than the primary thermal stresses, which means that the piezoelectric effect is negligible.
A thermo-mechanical numerical approach for the analysis of a historical rockslide in the Italian Alps
Authors: Morcioni A , Apuani T , Cecinato F 
Published: September 2021

Abstract
In this work, a thermo-mechanical (TM) numerical approach is presented and applied to investigate the stress-strain evolution of an alpine rock-slope located in the Central Italian Alps (Sondrio Province). Along the “Cimaganda” slope a massive rockslide event occurred around 900 A.D. mobilizing an estimated volume of 7.5 Mm3 of material, and reaching the bottom of the valley. Interest in this historic event was raised again in recent times, as a new rockslide took place in 2012, mobilizing 20.000 m3 of rock material and blocking the SS36 National Road.
To understand the general evolution of the Cimaganda rock slope, the recent geomorphological history of the Valley (post Last Glacial Maximum) was considered. In particular, to explore how glacial loading and unloading, associated with thermo-mechanical processes can promote rock mass damage, a 2D DEM numerical approach was adopted, calibrated upon the collected experimental and field data, and supported by a 2D FEM analysis to simulate transient heat diffusion over the Valley cross-section due to ice retreat and paleo-temperature evolution. Results show a clear relation between TM stresses and the occurrence of rock-mass damage and slip propagation along discontinuities. Simulated displacement and the development of a deep region of shear strain localization, allow to highlight the significance of temperature influence in preparing the rock slope to instability.
Comparison of depth-averaged and 3D models for dense granular flows
Authors: Pasqua A , Leonardi A , Pirulli M 
Published: September 2021

Abstract
Debris flows are one of the major threats to mountain communities. They consist of the downslope flow of fine and coarse material, saturated with water, along channelized paths. Due to their high velocity and unpredictability, the evacuation of hit areas may be difficult to execute. To avoid casualties and economic losses, mitigation structures, like filter barriers, are therefore usually adopted. Their primary task is to reduce the flow energy and to retain larger boulders. However, considerable room to improve the design of these structures still exists. In particular, gaining a better understanding of debris flows dynamics is a necessary step to improve the design of barriers. Numerical modelling can contribute to its understanding, and in an effective simulation of the flowing mass dynamics and impact against mitigation barriers. In this frame, the continuum-based Depth-Averaged Modelling (DAM) has been widely used since the 90s. In spite of the good results of this approach, together with the low computational time, the averaging procedure of velocity and pressure along the flow depth causes the loss of crucial information, which is important for correctly simulating the interaction with mitigation structures. A full 3D modelling can overcome this shortcoming by allowing a more complete flow representation, and a more accurate computation of impact forces. However, since debris flow may run for long distances, 3D models would require a large computational time. In this work we aim to study both the shortcomings and the advantages of the DAMs and 3D models. In particular, The DAM model used is DAN-W, while the 3D model is based on the lattice-Boltzmann method. To compare the results from numerical modelling, we use the experimental work performed by Moriguchi et al. (2009) in which a mass of dry sand flows on a steep chute.
Insights on squeezing behavior from Saint-Martin-la-Porte galleries
Authors: Liu Y , Sulem J , Subrin D , Tran-Manh H , Humbert E 
Published: September 2021

Abstract
In the context of the Saint-Martin-la-Porte survey project of the Lyon-Turin railway link, an access gallery (SMP2) was first excavated across a Carboniferous formation, where tectonized productive Houiller was met at a depth of 300 m. It exhibited a highly squeezing behavior, characterized by large, time-dependent and anisotropic deformation. Recently, a new survey gallery (SMP4) began to be excavated along the axis of the future base tunnel at a depth of about 600 m. Squeezing conditions have been met again when SMP4 crossed the same Carboniferous formation. Practical problems have been encountered related to the large and anisotropic closure of the cross-section and the instability on the tunnel face. On the basis of previous studies and numerical analyses of carried out for SMP2, the proposed methods are extended to SMP4 conditions. Numerical modeling is performed using FLAC3D code and the various phases of excavation and specific support installation are considered. The efficiency of the compressible elements in reducing the stress in the support system is demonstrated.
Stability modeling of complex underground mine openings integrating point clouds and FEM 3D
Authors: Agliardi F , Castellanza R , Frigerio G , Orlandi G M 
Published: September 2021

Abstract
The stability analysis of underground mine systems with complex 3D geometry is still a challenging task, especially when abandoned mines are planned for new uses with public access, that imply more restrictive safety requirements. This inherently multi-scale problem requires both the evaluation of the global mine stability and the assessment of local deformation and failure mechanisms of individual pillars or roof sectors in a robust 3D modeling framework. We integrated 3D remote survey techniques and FEM 3D modeling to perform a comprehensive stability analysis of an abandoned fluorite mine system in the central Southern Alps (Italy), including ten levels excavated in bedded limestones. We reconstructed the 3D geometry of three levels undergoing a reuse plan, combining a dynamic LiDAR system and close-range photogrammetry. We used point clouds in a workflow to generate solids, excavate the 3D analysis domain and generate a FEM 3D mesh for numerical modeling. We performed a series of continuum-based FEM 3D simulations of mine excavation and rock mass strength degradation. Our results allowed assessing the global stability of the abandoned mine and identifying critically stressed roof sectors and pillars to prioritize the local-scale analysis, remediation and monitoring of critical spots.
The driving force of all nature. Modelling water pressure and its stability consequences on alpine bedrock slopes
Authors: Scandroglio R , Stoll V , Krautblatter M 
Published: September 2021

Abstract
Hydrostatic pressure is one of the most important but still not fully understood destabilising factors of bedrock slopes. Water presence has often been recorded in major rock failures like at Piz Cengalo in 2017 but still its quantification and its effective destabilizing role remain unsolved issues in rockfall forecasting. Intensification of rainstorms due to climate change will enhance hydrostatic pressures in fractured bedrock, which will likely lead to increase in rockfall activity and connected risks for humans and infrastructures. Here we present a hydro-mechanical stability analysis of the Hochvogel summit (2,592 m AA) in the Northern Calcareous Alps. At this site, an imminent high-magnitude rockfall could destabilise up to 260,000 m3 and is therefore acutely monitored. Displacement measurements on the summit showed daily acceleration following intense precipitation. With the help of direct investigations and laboratory tests from previous studies, we implemented the Hochvogel SE slope and its mechanical parameters in the 2D Universal Distinct Element Code (UDEC). Our model shows that the presence of water columns of 10 m decreases the factor of safety (FoS) on average by 11 % and can increase the max displacement by up to 70 %. When including the effects of cleft weathering in the model, FoS < 1 can be reached. The friction angle of clefts has a key role in this destabilization process. This study provides key elements for interpreting the mechanical behaviour of this imminent rockfall in connection with hydrostatic pressures, helping to improve hazard forecasting at the Hochvogel and at similar sites.
Three-dimensional Distinct Element Method for stability analysis of marble quarries in the Apuan Alps (Italy)
Authors: Berlinghieri M , Pandolfi O 
Published: September 2021

Abstract
The present article analyses and proposes an innovative dynamic planning methodology, supported by computer tools and in-situ measurements, for the optimization of the planning techniques of underground marble quarries. The abovementioned planning methodology has been implemented in ‘Cava Piastreta’, an underground marble quarry located in the Apuan Alps, Italy. The entire excavation area has been characterized with tridimensional topographic surveys, geotechnical traditional surveys, and radar surveys, as well as stress-level measurement campaigns through a CSIRO cell. When an underground excavation project concerning stone material is designed, it is mandatory to have an instrument allowing a forecast of the stress-strain behavior of the rock mass. To this end, the rocky outcrop can also be represented by different mathematical models to schematize the geomechanical behavior. The accuracy and reliability of the simulation of the mechanical response of the fractured mass depend on the exactness with which the rocky outcrop is defined. Therefore, the geometric modeling phase acquires prominent importance. To better address the discontinuous nature of the studied rocky mass, the distinct element method has been used in modeling the mechanical behavior of the mass itself. Given the peculiar geometrical characteristics of the excavation site in question, the deterministic approach has been chosen to simulate as closely as possible the position of the major discontinuities identified in-situ. The present article thus aims to briefly describe a study that has been developed over the last years intended to deepen the analysis of the geostructural characterization of the excavation site, as well as to compare the obtained results through the geometrical tridimensional modeling with the values measured in-situ.