ISRM 2023 - PUBLICATIONS

T07: Geological risks and natural hazardsÖmer AYDAN (1), Yuki MURAYAMA (2), Takashi ITO (1), Naohiko TOKASHIKI (1)1: University of the Ryukyus, Okinawa, Japan; 2: Chuden Engineering ConsultantsThe assessment of dynamic stability of rock slopes with hexagonal jointing through shaking table tests and dynamic limiting equilibrium method (DLEM)The authors investigated the dynamic stability of rock slope consisting of hexagonal blocks through model tests on shaking table and evaluate their stability through dynamic limiting equilibrium method (DLEM). Experiments indicated that the failures may be toppling or sliding and, they may be of active or passive modes. Critical acceleration levels can be estimated from the limit equilibrium method if frictional properties of rock blocks and the geometry of model slopes together with appropriate consideration of failure modes. | Hexagonal jointing, dynamic limiting equilibrium method, dynamic, static, shaking table, slope
T07: Geological risks and natural hazardsDinesh JAGANIYA, Manish SHAH, Usha PATELDept. of Applied Mechanics, L D College of EngineeringEvaluation of natural foliation effect on deformation characteristic and shear strength parameters of Chamoli (Uttarakhand) rock using a Triaxial systemIn major part of the Chamoli, high degree of metamorphic rock are identified. The objective of this research paper is to examine the effect of natural foliation of Chamoli rock on shear characteristics and failure patterns through different anisotropic angles using an automated triaxial system. In present study, seven anisotropic angles (0°, 15°, 30°, 45°, 60°, 75°, and 90°) were simulated on a cylindrical specimen of diameter 50mm and length of 100mm based on the natural foliation of rock. From the experimental results and analysis based on Mohr-Coulomb and modified Hoek-Brown criteria, it is observed that the strength of rock decreased from 0° to 30° and the rock strength is continuously increased from 30° to 90°. Simulation of failure patterns in tested specimens are matched to anisotropy planes from 0° to 30°. As per above conclusion the natural foliation (anisotropic) behaviour is catastrophically affected on a strength and failure modes of Chamoli rock. | Anisotropic rocks, Natural foliation, Chamoli rock, metamorphic rocks, Modulus anisotropy, Triaxial system
T07: Geological risks and natural hazardsJeane Mokgadi MATSOBANE (1), Bryan Philip WATSON (2)1: Sibanye Stillwater, South Africa; 2: The University of the Witwatersrand, South AfricaAssessment of face area hangingwall stability in a hard rock bord and pillar mineThe aim of this project was to assist Triggered Action Response Plan teams to issue rapid yet comprehensive support recommendations in a production environment. The research was conducted in a shallow tabular hard-rock environment in a bord and pillar mining configuration. The assessment included evaluations of bord hangingwall behaviour under various geotechnical conditions, bord spans, face advances per blast, and the influence of the last line of permanent support. The results showed that the effectiveness of the last line of support is influenced by keyblock dimensions, particularly the perimeter exposure of these blocks in the hangingwall. A reduction in span and advance per blast were found to be beneficial in reducing the height of the potential falls of ground. A set of common failure conditions has been assessed and discontinuity orientations description is provided. The description of the condition is accompanied by recommendations of support configuration or suitable spans. | Face area, TARP, FOGs, Hangingwall, span
T07: Geological risks and natural hazardsChia-Chi CHIU (1), Wen-Jie SHIU (2), Ching-Fang LEE (2), Meng-Chia WENG (3), Che-Ming YANG (4)1: National Taipei University of Technology, Taiwan; 2: Sinotech Engineering Consultants Inc., Taipei, Taiwan; 3: National Yang Ming Chiao Tung University, Hsinchu, Taiwan; 4: National United University, Miaoli, TaiwanSystem of highway slope disaster information collection, integration, simulation and judgementLandslide and rockfall disasters frequently occur on road systems. Therefore, analyzing the disaster rapidly and deciding on the remediation method, is the key to reducing the loss. We have developed a ‘Highway slope disaster information collection, integration, simulation and judgment system’ which has three parts: (1) Geohazard rapid report system; (2) Multidisciplinary geological survey; and (3) Site-specific landslide simulation. This paper focuses on theYusui Stream debris flow and the disaster of the Minbaklu bridge as case studies to demonstrate the application of the aforementioned three components in disaster assessment. The key factor such as geological, terrain, distribution of weak plane, volume, process, and landslide mechanism, and finally provide a disaster report to concerned units for the assistance in follow-up decisions. | Slope, Disaster investigation, Information integration, Numerical simulation, Geological investigation
T07: Geological risks and natural hazardsHaojie YANG (1), Gan QI (2), Jili FENG (1), Zhengyuan LIU (1), Dejian LI (1)1: China University of Mining and Technology Beijing, People's Republic of China; 2: China Institute of GeoEnvironment MonitoringFailure mechanism and slip characteristics of landslides on loess plateau by continuous-discontinuous method: A case studyThis study focuses on the disaster-causing mechanism and sliding characteristics of sudden deep landslides in the loess area of Xiangning county of China. The continuous-discontinuous element method is employed to simulate the overall process of landslides from deformation accumulation to rupture and slip. The results show that the weak out-dip interlayer formed by long-term rainfall infiltration contributes to the landslides. The weak interlayer cannot provide sufficient anti-sliding force. Additionally, the soils at the leading edge exhibit a clear tendency of slipping at the beginning, and the mechanical process of landslide failure is shear-compression on the foot of the slope, shear in the middle, and pull crack at the trailing edge. During the sliding, the trailing edge sliding body obviously lags behind the leading edge sliding body. Finally, it is found that the numerical predictions are good in agreement with the field survey information of the loess landslides. | Landslides, Continuous-Discontinuous Method, Failure Mechanism, Slope Stability
T07: Geological risks and natural hazardsDaniele SPIZZICHINO (2), Paolo Maria GUARINO (2), Gabriele LEONI (2), Milena DILETTO (1), Edoardo LUSINI (1), Fabio PAGANO (3), Marida SALVATORI (3), Daniela BOLDINI (4)1: University of Bologna, Italy; 2: ISPRA, Geological Survey of Italy; 3: Parco Archeologico dei Campi Flegrei, Pozzuoli (Na), Italy; 4: Sapienza University of Rome, ItalyInstability phenomena affecting the cultural heritage cave of Antro della Sibilla (Cuma, Italy)The present work aims at the analysis of localized instability phenomena affecting the archaeological site of the Sibilla Antro. The cave was excavated by Greek colonists in the formation of Neapolitan Yellow Tuff, a pyroclastic weak rock. This rock is naturally fractured and weakly stratified: for these reasons local instability phenomena occurred along the whole extent of the Antro, worsened by the deterioration of past remediation interventions by passive dowels in the 1980s. Based on a geomechanical field survey and a laboratory characterization of the rock material, a 2D numerical model of the most threatened section was implemented to assess the stress concentration points and the current stability conditions. A proposal is also made for possible low impact measures for safeguard and conservation purposes. | weak rock, cultural heritage, instability, numerical analysis, Sibilla
T07: Geological risks and natural hazardsAline CONCHA-DIMAS (1), Ivan FABREGAT GONZALEZ (2)1: Institut Geològic de Catalunya. Presently: Universitat Autònoma de Barcelona, Cerdanyola del Vallès, Spain; 2: Institut Cartogràfic i Geològic de Catalunya, Barcelona, SpainGeomechanical and hydrogeological characterization of fracture systems in Banyoles Karst caprock units, CatalunyaBanyoles karst systems, located in NE Catalonia, is tectonically controlled, and associated to an artesian aquifer. This karst system is formed at the surface by a cap layer of competitive marls and calcareous rocks above a highly dissolving thick unit of gypsum with depth larger than 20 m. The voids left by upward water flow of the artesian aquifer generates sinkholes at the surface. First, we analyzed aerial photographs to describe the latest karst activity from 1945 up to the present. Secondly, we performed eighteen scanline surveys to describe the cap-rock structure (Jv and RQD) and describe hydraulic aperture and transmissivity (ac, Tf) of each joint set. In the cap rock units, we found up to 7 fracture systems that define medium-large block size. Two fractures have the highest Tf values, order of magnitude between 10-1 and 10-3, critical for the generation of collapses where the gypsum unit is shallow. | hypogenic karst, cap-rock units, unitary block size, hydraulic aperture, transmissivity, Banyoles Lake
T07: Geological risks and natural hazardsChristian BINDER, Anna FREUIS, Michael SCHREINER, Mathias SMESNIKAFRY Austria GmbH, AustriaRockfall hazards – Risk assessment, benefit/cost analysis and the design of flexible rockfall protection systemsRockfalls are a major threat to society and infrastructure in mountainous regions. The extension of settlement areas, linked with an increase in traffic combined with the people’s need for safety while driving on roads, make rockfall risk assessments and the employment of technical rockfall protection solutions indispensable. However, it is impossible to eliminate all economic and social risks caused by rockfall in mountainous regions. Risk assessments combined with benefit/cost analysis aim to reduce the risk in a structured and transparent framework to an acceptable level while maintaining cost efficiency. Technical risk reduction solutions like flexible rockfall barriers, etc. are effective but costly considering the initial investment and maintenance. This paper discusses the methodology and elements of a conducted risk assessment along with a benefit/cost analysis and how the same was used in the decision-making process of a rockfall hazard mitigation project for a section of a federal road in Austria. | Natural Hazards, Rockfall, Risk Concept, Risk Assessment, Benefit/Cost Analysis
T07: Geological risks and natural hazardsMatthias J. REBHAN (1), Hans-Peter DAXER (1), Markus SCHUCH (2), Franz TSCHUCHNIGG (1), Roman MARTE (1)1: Graz University of Technology, Austria; 2: ÖBB Infrastruktur AG, AustriaDevelopment of a double-corrosion-protected self-drilling micropile for the foundation of rockfall protection structuresThe construction of protective structures is one of the most important tasks of engineers in the field of natural hazard management. In addition to the often adverse environmental conditions during the installation of these structures, the inspection and the maintenance of such constructions is associated with a high level of effort. This paper presents a newly developed foundation method in the form of a self-drilling, double-corrosion-protected micropile. This component is expected to make a significant contribution in ensuring the durability of protective structures and a sufficient planned service life of more than 30 years. In addition, a brief outlook into the field of loads on protective structures and the suitability and acceptance testing of micropiles is given. Finally, the current status of the further development of the newly conceived micropile and the possibilities that such a system can offer are discussed. | micropiles, rockfall protection, corrosion, corrosion protection, foundation
T07: Geological risks and natural hazardsAhmed HOSNI, Claire MYR, Bastien COLAS, Isabelle HALFON, Yannick THIERY, Karim BEN SLIMANEBRGM, 3 avenue Claude Guillemin, Orléans, FranceStudy of the influence of anthropogenic galleries on the chalk cliff stability at Normandy region (France)The chalk cliffs are regularly subject to mass collapse phenomena in Normandy region (France). These instabilities represent some problems to manage for local authorities. In some cases, the chalk cliffs contain one or more galleries of anthropogenic origin and hazard assessment should integrate these particular contexts. Numerical modelling was developed in 2022 in order to quantify the influence of galleries on cliff’s stability. We studied the behavior of the {cliff + gallery} set according to parameters as the dimensions of galleries, their direction in comparison to the cliff direction (parallel or perpendicular), the superposition of exploited levels, the rock mass discontinuities, the mechanical properties of the overburden layers, etc. A scoring method is presented based on attribution of scores to the main parameters to determine the gallery influence on cliff’s stability. | Chalk, Cliff, gallery, stability, fracture, collapse, numerical model, distinct element method, plastic, mechanic, scoring
T07: Geological risks and natural hazardsFelipe GOBBI (1), Bruno DENARDIN DA ROSA (1), Dione Henrique DIAS (1), Fabio BERTUOL (1), Nataly AYUMI TOMA (1), Adoniran COELHO (2)1: FGS Geotecnia, Brazil; 2: ValeURUCUM Mine: Rockfall protection and monitoring systemThe access to Urucum mine is at the base of the Morraria de Urucum, composed of sedimentary rocks, a very steep rockface. Several rockfalls events in the past required that the company take action to mitigate risks, leading to a diagnostic and protective measures. Initially, the analyzes were based only on a point cloud, due access restrictions related to the pandemic period, resulting in a preliminary design of rockfall barriers and drainage. With the conceptual design, an extensive field mapping was performed, and the project revised, culminating in a drastic reduction of necessary interventions. The optimization it was possible through identification of differential weathering in the jaspilite strata, which allowed a new geomechanical model, better probabilistic analysis of block size distribution and thousands of rockfall simulations. This case is an interesting example of how the use of modern tools helps in projects, but it shows that they should be used with caution. | Rockfall, field mapping, point could, rockfall barrier, probabilistic analysis
T07: Geological risks and natural hazardsRainer KIENREICH, Alexander KLUCKNER, Thomas MARCHERInstitute of Rock Mechanics and Tunnelling, Graz University of Technology, Graz, AustriaRock Fall Risk – Modular Risk Management ProcessRockfall is an alpine phenomenon and must be understood as a risk. Due to the large number of events, detailed geotechnical investigations are not possible in many cases. In this article, a processing workflow is presented that enables an evaluation of a natural rockfall trigger risk. The trigger risk as well as the extent of damage are categorized in a risk matrix. The study of 485 outcrops at several rock slopes shows that without groundwater influence, predominantly stable conditions exist; with groundwater, the stability drops by around 20 %. In the case of a risk value of the "high" class, individual case assessments are necessary; in the case of the "medium" classification, organizational measures are required to minimize liability. | Rockfall, risk management, trigger risk, liability
T07: Geological risks and natural hazardsJian HUANG, Jingqing YUAN, Jianhong LIAOState Key Laboratory of Geohazard Prevention and Geoenvironment Protection, People's Republic of ChinaNumerical analysis of rockfall fragmentation mechanismFragmental rockfall is one kind of common geological disaster in mountainous areas. In this paper， the discrete element method, particle flow code (PFC) is used to simulate the impact and fracture process of rock mass， analysis the impact process of rock mass at different falling heights and impact angles， and the variation trend of impact force， velocity and the number of cracks in the rock mass. The results show that the velocity of rock mass decreases sharply and the crack develops rapidly after impact on the slope. With the increase in falling height， the rock mass velocity changes in a "second step shape"， and the number of broken blocks increases while decreasing the rock mass size. With the increase of slope angle， the "double peak phenomenon" of impact force becomes less obvious. The results provide a theoretical basis for the numerical simulation of fragmental rockfall and hazard assessment. | fragmental rockfall; PFC; impact angle; impact force
T07: Geological risks and natural hazardsLianjin TAO, Zhigang WANG, Zhibo JIABeijing University of Technology, People's Republic of ChinaFailure mechanism of the utility tunnel with flexible joints under reverse fault dislocationThe earthquake-damaged investigation found that tunnel structures crossed the active fault zone, and its affected area suffered the most severe damage. Through model tests and numerical simulations, the paper reveals the failure mechanism of the utility tunnel structure with flexible joints across the active fault zone. The results show that the damage range of the utility tunnel structure with flexible joints in the hanging wall is significantly larger than that of the footwall. The damage range is 2.5D and 1.25D, respectively. The utility tunnel structure is prone to stress concentration and damage in the corner area. The damage degree of the lining structure is classified according to the tensile damage factors, namely, no damage, slight damage, moderate damage, and severe damage. Combining the large deformation of flexible joints can effectively improve the design of tunnel structures across the fault zones and improve the seismic performance of tunnel structures. | Reverse fault; Utility tunnel; Flexible joint; Model test; Numercial simulation; mechanical response
T07: Geological risks and natural hazardsOlivier BUZZI, Davide GUCCIONEPriority Research Centre for Geotechnical Science and Engineering, The University of Newcastle, AustraliaEffect of shape on the survival probability of rock replicas during free fall testsFragmentation of rocks upon impact is a complex phenomenon that is not well understood. The first question to answer to adequately model fragmentation is whether a falling block is likely to fragment at impact or not. This question can be answered if the survival probability of the rock is known, but this is not trivial as no model or method exists to predict the survival probability of natural rocks. The authors have recently developed a model that can predict the survival probability of brittle rocks under collinear impact, following a preliminary breakthrough for brittle spheres. One complexity associated with irregularly shaped rocks is the possibility of non-collinear or eccentric impacts. The objective of this study is to conduct drop tests on irregularly shaped rocks and highlight the significance of collinear and eccentric impacts on the survival probability in drop tests. | Rockfall, Fragmentation, Shape, Survival Probability, Collinear, Eccentric
T07: Geological risks and natural hazardsMuriel GASC-BARBIER (1), Véronique MERRIEN-SOUKATCHOFF (2), Jean-Luc GENOIS (1), Charly MOUGIN (1), Pierre AZÉMARD (1)1: cerema, France; 2: le Cnam, France10 years of thermo-mechanical monitoring of rock columns - les chandelles de l’Escalette, FranceRock instabilities can represent major risks for local populations depending on their geographical location. Even if different factors such as precipitation, seismic activity and freezing, are known to trigger rockfalls it is more and more assumed that thermal cycling have a role in cracking initiation or propagation. Here we use data of the first six years of field monitoring of a 50-meter-high French dolomitic cliff, located above an important highway in the south of France (A75) to support this thinking. Evolution of the aperture of joints and temperature were followed on ten different locations around les Chandelles de l’Escalette. Results will be discussed in terms of mechanical response to temperature variations. | Thermomechanics, rock columns, monitoring, propagation, failure
T07: Geological risks and natural hazardsHippolyte DJIZANNE (1), Marwan AL HEIB (2), Aurélien GOUZY (1), Christian FRANCK (1)1: Ineris, Parc Technologique ALATA, BP 2, Verneuil-en-Halatte, France; 2: Ineris, Campus ARTEM, Nancy, FranceDevelopment of post-mining multi-hazard assessment methodologyMining, natural and technological hazards can occur in a former mining site. The multi-hazard analysis becomes critical. This paper aims to establish the methodological basis for assessing the interactions between the main hazards identified in abandoned mines. The interactions between 57 hazards are analysed based on: theoretical aspects, feedback analysis and expert opinions. Interaction matrices and loops are used, helping to study the interactions between hazards. | abandoned mine, multi-hazard, interaction, matrix, loop
T07: Geological risks and natural hazardsAbhijeet SINGH, Deepanshu SHIROLEIndian Institute of Technology, Delhi, IndiaExperimental simulation of mass flow characteristics for evaluation of the role of flow-bed roughnessOne of the significant geohazards associated with rock slopes is the avalanche. The mechanisms associated with such events are commonly studied under controlled settings of a laboratory scale analog as typical field conditions are inherently complex and uncertain. Accordingly, in this study, experiments on a novel laboratory-scale avalanche simulating system were performed to examine the flow and deposit characteristics of dry granular silica sand with the help of high-speed camera. The model consists of a fully regulated rigid flow-bed (0.6 m), on which the tests were performed at 36o, 42o and 47o angles of inclination, with frictionless (mica) and rough (P120 sandpaper) surfaces. The results showed that: (i) runout and deposit length on a smooth bed were greater than those on a rough surface, (ii) the height and width of deposit were greater on rough surfaces, and (iii) deposit width was not significantly affected by changes in the inclination angle. | Avalanche, bed friction, dry granular flow, granular mass deposit characteristics
T07: Geological risks and natural hazardsSusumu SHIBUTANI (1), Weiren LIN (2), Koichiro SADO (1)1: Chi-ken Sogo Consultants Co., Ltd., Japan; 2: Graduate School of Engineering, Kyoto University, JapanFracture characteristics obtained from core observations and image logs in a borehole drilled through an active fault zoneFracture characteristics in and around active fault zones are required for understanding hydrogeological characteristics along fault zones. To examine the fracture characteristics, we used core samples and geophysical log data collected from the Futagawa fault drilling project. Fracture density and angle of dip were quantitatively measured using core samples. As a result, the closed fractures with semiconsolidated brown clays were revealed dominant along the Fault 461 damage zone ruptured during 2016 Kumamoto earthquake mainshock, and the fracture density were higher in volcanic rocks than that in sedimentary rocks, and fractures were mainly oblique fractures with respect to the strike of the active fault. Kumamoto earthquake occurred at Fault 461 damage zone characterized by closed fractures, it suggests that the fault may have ruptured at the low permeability zone. | fracture density, active fault, core, image log, 2016 Kumamoto earthquake
T07: Geological risks and natural hazardsKosuke KAWATA (1), Minaho FUKUSHIMA (1), Akira MATSUOKA (1), Atsushi KUSAKA (2), Nobuharu ISAGO (1)1: Tokyo Metropolitan University, Japan; 2: Public Works Research Institute, JapanCharacteristics of reinforcement for earthquake resistance in mountain tunnelIn Japan, some mountain tunnels are damaged by earthquakes and relative large-scale deformations such as the collapse of permanent lining and the deformation of supports have occurred. Although the earthquake resistant countermeasures for tunnels has been examined recently, some countermeasures for existing tunnels are performed on the result of tunnel inspection rather than the need against earthquake resistance. To clarify the effects and the mechanical behavior of countermeasures, the model experiment was conducted assuming the structure of actual road tunnels. The collapse mechanism was compared among the cases when various kinds of reinforcement to tunnel were performed, such as rockbolts, fiber sheet and rebar. Results showed that the improvement of load-bearing capacity of the tunnel was limited, however the prevention of falling concrete blocks from structure could be expected. | mountain tunnel, earthquake, seismic measures, rehabilitation measures, experiment
T07: Geological risks and natural hazardsBenjamin COUGHLAN (1), Christian SAMPALEANU (2), Glyn WILLIAMS-JONES (1), Doug STEAD (1)1: Simon Fraser University, Canada; 2: Klohn Crippen BergerRockfall instability on high granitic domes: Stawamus Chief, B.C., CanadaThe rock slope stability of high granitic-granodiorite domes has become of increasing concern over recent decades. As tourism increases in popularity the risk posed by rockfall from these domes has also increased. Using the 417 m high Stawamus Chief, in Squamish, BC, Canada as a case study, we describe the use of multi-sensor remote sensing in understanding the failure mechanisms and the factors controlling instability. The Grand Wall and the North Wall of Stawamus Chief experienced significant rockfalls in 2021. Remote sensing using LiDAR and thermal imaging has added to our understanding of rockfall at Stawamus Chief. The application of these methods is discussed through detailed characterization of the rock slopes. Evidence shows that potential causal failure processes include root jacking, freeze-thaw effects, heavy precipitation, and expansion of joints due to extreme heat. | Geohazards, Remote Sensing, Slope Stability, Rock Mechanics, Rockfall
T07: Geological risks and natural hazardsNathalie CONIL (1), Clara MAGHAMI (2), Marwan ALHEIB (1), Philippe GOMBERT (1)1: Ineris, France; 2: Ecole des MinesImpact of climate change on the collapse of shallow mines – feedback from FranceFor many years, Ineris has been conducting research on the impact of climate change on the stability of abandoned mines. In this context, work has been initiated to reference cases of shallow mine collapses. So far, 480 cases have been identified and described. Preliminary analysis of the information gathered shows that 50% of the cases correspond relate to chalk mines, 32% to limestone mines, and 16% to gypsum mines. Two case studies presented in the paper were also analyzed in more detail. Complexity of the water-rock interaction and the importance of studying more precisely the various parameters impacted and their relationships are highlighted. Therefore, a chalk mine located in Seine-et-Marne (France) was instrumented to monitor the evolution of the structure over time and analyze the different causes of degradation. The objectives are to better understand the behavior of these structures to be able to detect precursor signs to these collapses. | shallow abandoned mines, aging, collapse, climate change, water-rock interaction
T07: Geological risks and natural hazardsJohannes BRANKE (1), Jan PFEIFFER (2), Thomas ZIEHER (3), Magnus BREMER (1), Martin RUTZINGER (1), Bernhard GEMS (1), Margreth KEILER (1,2), Barbara SCHNEIDER-MUNTAU (1)1: University of Innsbruck, Innsbruck, Austria; 2: Austrian Academy of Sciences, Innsbruck, Austria; 3: Austrian Research Centre for Forests (BFW), Innsbruck, AustriaClosing the gap from spatio-temporal displacement monitoring to geomechanical process understanding of cascading multi-hazards caused by deep-seated gravitational slope deformationsActive deep-seated gravitational slope deformations (DSGSDs) and interlinked secondary processes such as rockfalls and debris flows pose multiple threats to livelihoods in mountain regions. A currently active part (~0.35 km2) of the Reissenschuh DSGSD (Schmirn valley, Tyrol, Austria) shows considerable displacement rates of about 1 m per year. This remarkable relocation of material constantly changes the topography and leads to a pronounced activity of debris flow and rockfall at the landslide toe. This contribution focuses on understanding the interactions of DSGSD activity (rock mass supply) and interlinked cascade dynamics to assess their complex triggering mechanisms and related secondary processes. It gives an overview of previous and ongoing monitoring campaigns and presents preliminary findings on cascade process interactions. | Natural hazard research, deep-seated gravitational slope deformation, cascade multi-hazard, landslide
T07: Geological risks and natural hazardsMaria Lia NAPOLI (1), Monica BARBERO (1), Marta CASTELLI (1), Francesco CASTELLI (2)1: Politecnico di Torino, Italy; 2: Università degli studi di Enna "KORE"An approach to assess the detachment propensity of rockfall source areas: the Susceptibility Index to Failure (SIF)This paper proposes a practical approach to assess the susceptibility of rock slopes to produce rockfalls. Once identified the potential release areas, a rockfall Susceptibility Index to Failure (SIF) can be assigned to distinguish among prone areas with detachment propensity from 0 (null probability) to 1 (maximum probability). This index can be defined according to the presence and intensity of several causative factors, which were identified and scored on the basis of the scale of interest and the environment considered. Specifically, the small and the detailed scales and the mountain and coastal-marine environments were considered. An application example is presented to illustrate the validity of the proposed approach. | rockfall, detachment propensity, causative factors, Susceptibility Index to Failure (SIF), susceptibility maps
T07: Geological risks and natural hazardsPai-Chiao LO (1), Wei LO (2), Yong-Zhi HUANG (1), Ya-Chu CHIU (3), Tai-Tien WANG (1), Yu-Chung HSIEH (4)1: National Taiwan University,Taipei, Taiwan; 2: National Taipei University of Technology, Taipei, Taiwan; 3: National Chung Hsing University,Taichung, Taiwan; 4: Central Geological Survey, New Taipei, TaiwanSlope stability and engineering characteristics of rock mass at the boundary of slate and schist: Study of Southern Cross-Island Highway in southeastern TaiwanThe slopes in the study area had suffered from frequent collapses. To investigate the relationship between slope instability and the engineering parameters of the rock masses at the boundary of slate formation and Tananao schist formation, interpretation of the spatial distribution of collapses from multi-temporal remote sensing images, investigation of slope instability mechanism, surveying and geological mapping, and evaluation of engineering parameters of rock masses have been performed and reported in this article. The outcomes indicate that the Q values of the rock masses at the boundary of slate and schist are lower than those of the surrounding rocks, resulting in areas prone to rock slides, debris slides, and rock fall. The adaptive structures, such as axial faults, pre-existing shear, and dense fractures near the axis of a mesoscale fold, cause rock fragmentations, which are often the source of rock debris and rock fall. | slate, schist, landslide, slope instability, fold
T07: Geological risks and natural hazardsKatsumi KAMEMURAFukada Geological Institute, JapanSeismic resistance evaluation based on earthquake damage survey data of mountain tunnelsTunnels constructed in the rock formation have been considered safe against earthquakes. However, the 1995 Hyogo-ken Nanbu Earthquake (M7.3) caused large damages to mountain tunnels as many as to other structures. Tunnels are one of the important infrastructures, so the evaluation of seismic resistance is a very important issue. Here damage reports on the 1923 Kanto Earthquake, the 1995 Hyogo-ken Nanbu Earthquake, the 2004 Niigata-ken Chuetsu Earthquake and others in total seven earthquakes are studied and the seismic resistance is evaluated as in the relationship between the seismic intensity and the damage rate. Using this relationship and the earthquake probability provided by official organization, the seismic risk that is very useful tool to plan appropriate earthquake countermeasures can be evaluated. | Mountain tunnel, Seismic damage, Seismic resistance evaluation, Seismic risk
T07: Geological risks and natural hazardsMaddalena MARCHELLI, Valerio DE BIAGIPolitecnico di Torino, ItalyEvent tree analysis and time-integrated reliability design approach for quantifying rockfall risk reductionThe quantification of risk in terms of loss of lives represents the essential parameter to manage rockfall risk in urbanized areas. Rockfall barriers are among the most adopted structural mitigation measures. Despite their wide use, the partial safety factors design approach is not able to guarantee a specific failure probability and, consequently, to assess the precise risk reduction. To tackle all these issues, a quantitative risk assessment method for infrastructures and a time-integrated reliability design approach for rockfall barriers developed by the Authors are combined in a unique framework to quantify risk reduction. The former computes the risk as annual probability of having at least one fatality; the latter allows defining an annual failure probability for a given product in a given site. Merging these methods, the evaluation of risk reduction in case of barrier installation or the definition of the required performances, are defined. An example of application is provided. | Rockfall Risk, Reliability based design, Event tree Analysis, Rockfall barrier
T07: Geological risks and natural hazardsJoão Paulo MONTICELLI, Rogerio RIBEIROSão Carlos School of Engineering University of São Paulo, São Paulo, BrazilA study case of a rockfall event in a geomorphosite from the Corumbataí Geopark Project, state of São Paulo, BrazilMany geomorphosites are under a natural risk scenario, as those from the Corumbataí Geopark Project, state of São Paulo, Brazil. This paper shows a rock fall event in the Camelo Hill geomorphosite. The area is used by walkers, climbers, mountaineers and civilians in general as a touristic spot in the Geopark domain. In October 2022, a boulder fell from the cliff and destroyed many trees along the slope until stopping at the dirt road used for local tourism. Herein, we have identified the rock detachment source area using field investigations and UAV mapping; an inventory of rockfalls was created and compared to the recent event. Characteristics of the rock travel distance were raised to guide the local authorities. This study also presents a new kind of source area, a rock fall conceptual model for tropical conditions, created to elucidate the mass movement to civilians. | Rock fall, drone, conceptual model, travel distance, geomorphosite, geopark
T07: Geological risks and natural hazardsAdeline DELONCACenter for Research and Innovation in Mining (CIIM), Geomechanics Research Group, Department of Metallurgical Engineering and Materials, Universidad Técnica Federico Santa María, Santiago, ChilePredicting geomechanical hazard: utopia or reality?Geomechanical hazard can be defined as a combination of the probability occurrence of an event and its intensity. Therefore, predicting a hazard level should give information about how (phenomenology of the failure), when (exact time of failure), and how much (with which intensity in terms of volume and energy) the event will occur. Several methods have been developed over the years to assess some or all these components. However, they do not allow a prediction to be made in terms of the time, location, and magnitude of the event. Indeed, in this assessment process, uncertainties are met at each step. Therefore, the prediction could be reached by answering two questions: can we remove all uncertainty? And if we do not have any uncertainty: are we able to predict the hazard? This paper proposed to discuss the two presented questions by going through various works realized during the author’s academic career. | Geomechanical hazard, uncertainties, risk assessment, prediction
T07: Geological risks and natural hazardsZheng GONG (1), Jang-guen LEE (1), Gyu-Hyun GO (2)1: Future Smart Construction Research Division, Korea Institute of Civil Engineering and Building Technology, Republic of Korea (South Korea); 2: Department of Civil Engineering, Kumoh National Institute of TechReview and evaluation of Porosity Rate Model (PRM) for highly frost susceptible soilsFrost heave is a frost action when the soil temperature is below freezing temperature. Construction in cold regions is difficult and might cause serious damage to structures. Therefore, it is important to estimate frost heave before construction. The purpose of this study is to introduce and modify a model that can predict frost heave behavior through the change in soil porosity. The Porosity Rate Model (PRM) is possibly applicable for engineering purposes in describing the frost heave process, but the previous studies only focus on clayey soils which may not be frost susceptible soils. This paper presents an assessment of PRM on frost susceptible soils prepared by sand-silt mixtures. Comparisons were made by comparing the predictions obtained with the same initial conditions on the PRM using frost heave data for frost-susceptible soils. Results show good agreement between them, PRM was found to be equally applicable to frost-susceptible soils. | Frost Heave, Porosity Rate Model, Frost Susceptible, Silt
T07: Geological risks and natural hazardsReinhard GERSTNER (1), Christine FEY (1), Klaus VOIT (1), Erik KUSCHEL (1), Gerald VALENTIN (2), Christian ZANGERL (1)1: Institute of Applied Geology, University of Natural Resources and Life Sciences, Vienna (BOKU), Austria; 2: Landesgeologischer Dienst, Land Salzburg, AustriaKinematic Analysis and Distinct Element Modelling of a polyphase Rock FallRock falls are one of the most hazardous mountain processes and can show variable failure mechanisms. Therefore, a kinematic analysis is commonly performed to assess which failure mechanisms are favoured by the structural inventory of a rock mass. However, often multiple failure mechanisms are thereby considered possible. In our paper, we emphasize this ambiguity and investigate factors controlling the actual rock fall failure mechanism. For this purpose, we have selected a case study in southern Salzburg (Austria), where three rock falls occurred from a highly schistose, metamorphic rock mass in the year of 2019. In our study, we characterized the structural inventory of the rock mass hosting the rock falls and identified possible failure mechanisms by a kinematic analysis. Through distinct element modelling, we show that depending on the persistence of pre-existing structures, the reproduced failure mechanism alternates between the kinematically proposed mechanisms, i.e. block toppling and sliding. | rock fall, initial failure mechanism, kinematic analysis, structural control, distinct element modelling
T07: Geological risks and natural hazardsGiulia TORSELLO (1), Marta CASTELLI (1), Michele MORELLI (2)1: Politecnico di Torino, Italy; 2: ARPA Piemonte, Regional Agency for the Protection of the Environment, Turin, ItalyThe collapse of Torrione Sucai (Mt. Viso, Italy): rockfall analysis and data calibrationIn December 2019 a large collapse affected the Torrione Sucai, a rocky structure located on the North-Eastern slope of Mt. Viso (Italy) at about 3100 m a.s.l. Mt Viso has been included in the UNESCO World Heritage Sites since 2013 as a biosphere reserve. Therefore, hazard and risk assessment is a priority for the protection of people and the environment. The rockfall was triggered by a combination of high fracturing of the rock mass and permafrost degradation, with associated phenomena that weakened the rock mass and created conditions for slope instability. This study entails a multi-scale analysis of fracture distribution and intersections, in order to identify the zones most prone to collapse. Moreover, a multi-scale back analysis of the run-out behavior of the 2019 rockfall was performed. The results were used to calibrate preliminary susceptibility analyses for the entire area, presented and discussed in the paper. | climate change, permafrost degradation, rockfall, Italian Alps, Mt. Viso
T07: Geological risks and natural hazardsJeoung Seok YOON (1,2), Anne STRADER (1), Jian ZHOU (3), Soo-Gin KIM (4), Jae-Yeol CHEONG (4)1: DynaFrax UG, limited liability, Germany; 2: Handong Global University, Korea; 3: Beijing University of Technology, China; 4: Korea Radioactive Waste Agency, KoreaNumerical Modelling Study of the 2016 Gyeongju Earthquake Rupture Process and Correlation with Groundwater Level ChangeCoseismic changes in groundwater level have been reported worldwide, particularly in areas of moderate to high seismicity. These variations are often attributed to redistribution of stress and strain, which can reactivate fractures, joints and microcracks through local changes in fluid pressure. Such variations were observed following the September 2016 ML 5.8 Gyeongju earthquake in South Korea, rupturing the Yangsan fault at a depth of 11–16 km and producing strong high-frequency ground motions. To better understand and quantify local stress changes and subsequent changes in fluid migration patterns within this area, we have developed a discrete element model (DEM) of the Yangsan fault network using the Particle Flow Code (PFC2D) software. Spatial distributions of local Coulomb stress changes are in good agreement with stress changes reported in literature. Furthermore, a weak but positive correlation is observed between the amount of groundwater level change and increased stress. | Discrete element model, numerical modeling, rupture simulation, Korean seismicity, fluid migration
T07: Geological risks and natural hazardsHyung-Mok KIM (1), Yashwanth Kumar GUJJALA (1,2), Junya INOUE (3), Dong-Woo RYU (4)1: Sejong University, South Korea; 2: Indian Institute of Technology (Indian School of Mines), India; 3: The University of Tokyo, Japan; 4: Korea Institute of Geoscience and Mineral Resources, South KoreaAn improved calibration and uncertainty analysis for a ground subsidence using physics-informed neural network (PINN) approachAccurately estimating surface settlement requires assessing under-bed layer properties. However, limited information necessitates the use of computational methods to address uncertainties. Recent advancements in machine learning and physics informed neural networks (PINN) have allowed researchers to incorporate physics into neural network models, enabling the forecasting of necessary parameters using inverse analysis algorithms. In this study, we employ the PINN approach to estimate unknown parameters associated with under-lying clay layer thickness and consolidation-aided material constants in an offshore vicinity of a river delta area. We implemented and compared Mikasa's one-dimensional approach, and also compared the outcomes of PINN techniques with Terzaghi's one-dimensional analytical solution and PEST back analysis. Additionally, our work introduces a methodology that utilizes PINN to identify these attributes and explores potential future applications of this framework. | PINN, Consolidation, Subsidence, Uncertainty