ISRM 2023 - PUBLICATIONS

T10: MonitoringKazuo SAKAI (1), Toshifumi AKAKI (1), Yoshimi OHNISHI (1), Shigeru TANAKA (2), Tomonori HORIDOME (2)1: Taisei Corporation, Japan; 2: Toa Elmes, JapanDevelopment of tunnel pre-displacement measurement method by fiber optic sensingThe authors developed a measurement method by the fiber optic sensing which can evaluate vertical and lateral displacements ahead of the tunnel face. The method uses some fiber optic cable sensors named All Grating Fibers capable of evaluating the longitudinal strains along the cable with high positional resolution and accuracy by the Optical Frequency Domain Reflectometry method. The cable sensors are fixed with inflatable packer tubes in a square pipe inserted in a steel forepole drilled from the face and can be retrieved after the measurement. One advantage is therefore the fact that fibers can be repeatedly used in other pipes. This paper outlines the developed tunnel pre-displacement measurement method by the fiber optic sensing. Results of laboratory experiments and field measurements conducted in a motorway tunnel construction project are also presented. | Pre-displacement measurement, Fiber optic sensing, All Grating Fiber, Optical Frequency Domain Reflectometry
T10: MonitoringJiayong TIAN (1), Kanghua ZHANG (2), Jiashu LOU (1)1: National Institute of Natural Hazards, MEMC, People's Republic of China; 2: Tianjin University, People's Republic of ChinaNext-generation high-resolution borehole tensor strainmeters for the measurement of six strain-components based on fully automated interferometric displacement sensorsConventional borehole tensor strainmeters (BTSM) based on the measurement of inner-diameter changes of strainmeters by four capacitance gauges had been developed to measure three strain-components in the horizontal plane. The other three strain components are also important, but are difficult to implement because of large volume of sensors. In order to measure six strain-components completely, we develop a new high-resolution BTSM based on a fully automated interferometric displacement sensor with fibre-based heads of the millimeter dimension,which makes the gauge ultra-compact to implement the four inner-diameter-change measurement and other three-gauge measurements considering the influences of strain components in the plane of vertical normal. Compared with conventional BTSM, the impulse hammer test results show that gauge design of the new BTSM extends measurement resolution from 10-9 to 10-12 and increases the measurement bandwidth greatly, which advances the technology of borehole strain. | High-resolution borehole tensor strainmeters, Fully automated interferometric displacement sensors, six strain-components, Next-generation
T10: MonitoringFerenc DEÁK (1,4), Ákos TÓTH (2), Tomas MÁRIK (3)1: SeklerGeo, Hungary; 2: TunnelTech Ltd., Hungary; 3: Geoinspect Ltd., Cech Republic; 4: Budapest University of Technology and Economics, HungaryDetermination and validation of Longitudinal Displacement Profile by in situ measurements at the M85 motorway tunnelTunnelling is an obviously three-dimensional process. Tunnelling in yielding ground also generates a 3D, bullet shaped zone of plasticity in soft rock, but also generates a bullet shaped fracture zones in the brittle rock masses. Longitudinal displacement profiles (LDP) characterize and describe the displacement history during tunnel excavation, including that occurring ahead of the tunnel face. Experimentally determined LDP provide a valuable database for validation of the tunnelling approaches. This study is presenting the in-situ measurements of two geotechnical instrumentation sections which includes MPBX extensometers and NATM pressure cells from the shallow depth M85 motorway tunnel which is excavated in soft ground and is situated beside Sopron city (Hungary). The measurement results give us opportunity to validate the LDP and to verify the tunnel support interaction with the tunnel excavation. The results show good qualitative and quantitative agreement ahead of the tunnel face. | Longitudinal Displacement Profile, MPBX extensometer, NATM pressure cell, deformation, excavation
T10: MonitoringSharla COETSEE (1), Priyanka NARSHAI (1), John-Philip TAYLOR (2)1: Reutech Mining, South Africa; 2: Reutech Radar Systems, South AfricaAn overview of RAR application for pit slope monitoring: with a focus on spatial and temporal resolutionAn overview of Real Aperture Radar (RAR) for pit slope stability monitoring is provided, with a specific focus on spatial and temporal resolution based on the physics utilised by the system. For the purpose of this paper, the RAR system discussed is the Reutech Mining Modular Movement and Surveying Radar (MSR). The system is deployed at a position whereby it is mechanically steered to conduct sequential interferometric measurements to delineate deformation data from the pit slope. The area that may be scanned is definable, and comprises 186° in azimuth and 129° in elevation. The sample acquisition time (temporal resolution) is dependent on the scan rate. The spatial point resolution is defined by user selected options. The radar is georeferenced in order to allow for 3D identification of synthetic map points and therefore the interrogation of data from potential areas of concern, which may indicate instability of the pit slope. | Real Aperture Radar (RAR), spatial and temporal resolution, monitoring, deformation, instability
T10: MonitoringEdo NOORDERMEER (1), Roland BEKENDAM (2), Karlijn BEERS (1), Auke NACHENIUS (1), Devrez KARABACAK (1)1: Fugro, The Netherlands; 2: GeoControlMonitoring the rock-mechanical safety of underground limestone quarries using fibre optic sensing technologyA fibre optic monitoring system has been installed in two limestone quarries in Valkenburg aan de Geul, The Netherlands, to monitor pillar stability and to give early warning of locations at risk of collapse. The system is highly sensitive and can detect creep deformation of the pillars as small as 1 micrometer. Measurements are displayed via a web-based data portal and alerts are triggered if the creep velocity exceeds pre-determined thresholds or if creep accelerates. We present the design of the monitoring system and results from the first three years of operation. We show examples of the natural behaviour of the pillars and we present a number of deviating patterns that sparked particular interest. We also share some lessons learnt that can be used when designing and installing similar systems in other quarries, caves or mines. | Monitoring, safety, limestone mining, fibre optics
T10: MonitoringRoberto SARRO (1), Juan LÓPEZ-VINIELLES (1), Adrián RIQUELME (2), Mónica MARTÍNEZ-CORBELLA (1), Juan Carlos GARCÍA-DAVALILLO (1), Augusto RODRÍGUEZ (1), José Antonio FERNANDEZ-MERODO (1), Ángela SUÁREZ-RODRÍGUEZ (1), Mario HERNÁNDEZ (1), Rosa María MATEOS (1), Mercedes FERRER (1), Joaquín MULAS (1)1: Geological Survey of Spain (IGME-CSIC); 2: University of AlicanteAnalysis of the evolution of a reclaimed coal mining area using historical aerial photographsMining activities have a significant impact on the environment, and it is crucial for mining companies to restore the land after extraction and preserve the original landscape. Remote-sensing techniques, such as Structure-from-Motion and 3D laser scanners, have become widely used in mining for ground monitoring due to their accessibility and safety advantages. In this study, historical aerial optical imagery of a coal-mining site in León, Spain, was processed using SfM photogrammetry to analyze landscape changes from the beginning of the open-pit operation to the completion of land reclamation. Two point clouds generated from open-access optical imagery were compared with a LiDAR point cloud from 2010. To ensure accurate georeferencing, ground control points were extracted from an additional LiDAR point cloud acquired in 2010. By comparing these reconstructions and conducting a comprehensive analysis of the site's evolution, the researchers identified a landfill and assessed the effectiveness of the mine reclamation works. | Landslide, Coal mining, SfM, Land restoration, Aerial photographs
T10: MonitoringSepidehalsadat HENDI, Erik EBERHARDT, Mostafa GORJIANUniversity of British Columbia, CanadaDevelopment of a non-destructive stress measurement method using distributed fiber optic sensing and geophysical techniquesIn-situ stress is a critical boundary condition that dictates many important rock engineering design decisions such as the orientation, dimensioning and support design of underground excavations for mining and civil infrastructure to ensure stability and safety, as well as the optimal orientation of horizontal boreholes for energy development projects (geothermal, unconventional gas). However, it is also one of the most difficult parameters to measure reliably, resulting in significant uncertainty and risk to these projects. This has seen the development of numerous stress measurement techniques, each with its limitations and reliability issues. Presented here are the first steps in the conceptualization and workflow for a non-destructive stress measurement technique using distributed fiber optic sensing and geophysical techniques that overcomes several key challenges and limitations, while adding value through increased measurement resolution and reliability. Numerical workflow results are presented that compare favorably with values based on experimental results. | In-situ stress, distributed sensing, fiber optics, stress measurement, borehole geophysics
T10: MonitoringVlastimil KAJZAR, Eva JIRANKOVA, Petr KONICEKInstitute of Geonics, Czech Academy of Sciences, Czech RepublicFirst experience with the newly created monitoring system of dynamics of surface changes occurring during the transition into the post-mining stageThe study of the manifestations of mining cannot be done without a technology that allows monitoring the dynamics of surface changes. The Automatic Geodetic Monitoring System was developed to obtain measurement data on surface movements at the CSM coal mine. This system will provide data of sufficient frequency and quality to evaluate the surface deformations caused by deep mining. Long-term monitoring will generate a dataset suitable for developing a method for assessing the consequences of mining after mine closure. The monitoring system consists of two automatic total stations with an integrated 3D laser scanner, GNSS sensors and other accessories. The monitoring period was set to cover, at least in part, the main phase of surface movements caused by underground mining and their subsequent fading in time. However, it is important to note that measured data accuracy can be affected by various adverse factors, prompting ongoing enhancements to the monitoring system. | subsidence, MultiStation, monitoring, hard coal, mining, post-mining
T10: MonitoringGhader SAADATI (1,2), Michael METT (2), Kontrus HEINER (2), Barbara SCHNEIDER-MUNTAU (1)1: Unit of Geotechnical Engineering, Department of Infrastructure Engineering, University of Innsbruck, Austria; 2: Dibit Messtechnik GmbH, AustriaUsage of Monitoring Data to Optimize and Validate the Geotechnical Parameters of Rock Properties in the Underground SpaceDetermining parameters, including geomechanical characteristics of rocks or rock mass, initial stress state, underground water conditions, permeability, etc., with high accuracy is difficult and expensive due to the complexity of the geological conditions. On the other hand, analyzing the stability of tunnels and determining the behavioral characteristics of the rock mass with numerical methods has limitations in terms of the validity of the input and output data. One of the practical methods to solve these problems is the use of monitoring system in underground space, which aims to measure displacements and can give an estimate of the stability of structures and rock mass. One possible way to validate or determine parameters on site is the use of precision instruments and perform back analysis on the resulting deformation data. In this research, different back analysis methods are investigated to validate rock masses parameters in tunnels. | Monitoring system, Back analyse, Numerical methods, Underground space, Rock mass parameters
T10: MonitoringMiguel PAGANIN NETO, Elder Lucas RIBEIRO, Christiano NOGUEIRA, João Pedro DELVEAUX, Wesley de Lima SILVA, Camilla Szerman EUZEBIOVALE S.A.Optimization of a large-scale slope monitoring system by the correlation between interferometric radar and geological compartmentalizationThe implementation of a monitoring system able to catch geotechnical events in large-scale open pits is challenging and requires a combination of different technologies, since rock masses are heterogeneous. Traditional monitoring systems commonly treat rock masses as a discrete and homogeneous domain, which is not representative of the global slope failure process with differentiated deformation along the structure, due to different rock types, joint families and rheology. Interferometric radars have been used as a potential tool in monitoring large-scale geotechnical failures, since they could give a rapid response in all scale deformation, characterize the behavior of the movement, and predict failure time using tools, as inverse velocity. Regardless of the scale of slope monitored, the data obtained is rarely associated with rock types and rheology. This article presents an optimization of a large-scale slope monitoring system, correlating interferometric radar and geological compartmentalization, in a real case of global slope failure. | monitoring system, terrestrial radar, global slope failure, rock mass, sectorization
T10: MonitoringAlbert GREINMEISTER (1), Johann GOLSER (2), Alexander RADINGER (2), Gernot JEDLITSCHKA (3), Manfred EDER (4), Micheal FELDINGER (5), Franz RATHMAIR (6), Erich SAURER (7)1: Salzburger Regionalstadtbahn Projektgesellschaft mbh, Salzburg, Austria; 2: Geodata Surveying and Monitoring Group, Leoben, Austria; 3: JV TSS – Team Schiene Salzburg, Puch, Austria (Geoconsult ZT GmbH); 4: JV TSS – Team Schiene Salzburg, Puch, Austria (Laabmayr ZT GmbH); 5: JV TSS – Team Schiene Salzburg, Puch, Austria (IGT Geotechnik und Tunnelbau ZT GmbH); 6: Keller Grundbau GmbH, Linz, Austria; 7: Skava consulting ZT-GmbH, Salzburg, AustriaMonitoring and analysis of the behavior of the Salzburg-Clay during the jet grouting works for the S-LINK projectThe underground railway line project S-LINK aims for a fast rail connection within the Greater Salzburg Area. The alignment in the first section, starting from Salzburg main station southwards runs underground. The subsoil along the alignment consists of a few meters of fill and gravel in the uppermost section, followed by fine sand-dominated and silt-dominated lacustrine deposits with varying clay and a high water content, which are locally referred to as "Salzburger Seeton". In order to increase the robustness and reliability of the design and optimize the relevant construction parameters, the jet grouting method and its effect on adjacent soil and structures were tested in a test field. The main purpose of these tests was knowledge acquisition for the best possible application of the method under the given geological conditions as basis for design. In this article, the relevant boundary conditions, objectives and results of the test field are presented. | Monitoring, Data Acquisition, Jet Grouting
T10: MonitoringMuammer BERBEREldorado Gold (TUPRAG Efemcukuru Gold Mine), TurkeyGeotechnical Risk Assessment and Management with Underground Controls and Monitoring System for Sill Pillar Recovery at Tüprag Efemcukuru Gold MineGeotechnical assessment was used to define the mining method, the production schedule, and potential risks for the recovery of sill pillar left at two levels, namely 555 Level and 595 Level. According to geotechnical assessment production was planned for the pillar by using transverse blind up-hole stopes, which are accessed via drift driven in orebody, on the hanging wall side where was planned to monitor the ground movement with smart cable bolt. Consequently, records and cracks along hanging wall, potential risk was detailed with re-assessment that involved the elastic deformation of the paste fill measured in UCS tests were used to anticipate the regional displacement. Also, another instrument named smart MPBX’s were used for modelling accurate movement. All results of monitoring have been recorded and correlated with mining activities. In conclusion, a new access drift on the footwall has been designed and the production sequence and schedule has been updated. | Smart, Cable, MPBX, Monitoring, Assessment, Geotechnical
T10: MonitoringBartolomeo VIGNA, Adriano FIORUCCI, Federico VAGNON, Marco BARALEPolitecnico di Torino, ItalySinkholes and underground mining activities: the key role of monitoring for the hazard assessment and mitigationIn 2005, the exploitation activities in the Moncalvo underground gypsum quarry in the Monferrato area (Moncalvo, Piedmont Region, NW Italy), intercepted a karst cave filled with pressurized water (0.3 MPa). After this event, a hydrodynamic and hydrogeochemical methodology was developed and coupled to direct observations to monitor the water flows into the quarry. In particular, all the existing water flows and the new ones generated by the mining activities were mapped. Redox potential, electrical conductivity and water temperature were recurrently measured and integrated with chemical analyses. Piezometric levels were also measured in many piezometers located around the quarry site. The proposed methodology was successfully applied to the Calliano gypsum quarry, which is located in the same geological framework but it is representative of a different karst system. The paper highlights the key role of the hydrogeochemical monitoring as a potential technique for the sinkhole risk related to mining activities. | sinkholes, gypsum, hydrogeochemical monitoring, karst hydrogeology
T10: Monitoringİhsan ÖZKAN (1), Mehmet MESUTOĞLU (1), Mahmut Yasin ÇETINKAYA (2)1: Konya Technical University, Konya, Turkey; 2: Turkish Coal Enterprises (TKİ)-Ömerler Underground Coal Mine, Kütahya, TurkeyA new in-situ monitoring system to determine stability of underground coal pillar subjected to dynamic loading: electrical resistance measurement system (ERMS)The electrical resistance measurement system (ERMS) was tried to be developed. The first in-situ applications were carried out in A6 panel in GLİ underground coal mine. As perpendicular to the pillar face, two parallel boreholes with 4 m long and interval 30 cm were drilled. The copper plates with a width of 200 mm and a thickness of 0.5 mm was wrapped on the measuring rod with 50 cm intervals and also soldered with copper wires. Then two rods were separately inserted into boreholes named as ERMS-#. In this way, 5 stations were installed with 5 m intervals. Measurements were carried out by ohmmeter using each electrical wire coming from the copper plates located at the same depth of boreholes. ERMS values measured on pillar subjected to dynamic loading due to longwall mining operations were shown that there were unstable in the first 2.5 m region of the pillar side. | Longwall coal mining, Coal pillar, In-situ measurement, Electrical resistance behavior
T10: MonitoringShoji YUKIKO (1), Kikuchi TERUYUKI (2), Koike HITOSHI (3), Shimizu NORIKAZU (4)1: Electric Power Development Co., Ltd., Chigasaki, Japan; 2: J-POWER Design Co., Ltd., Chiyoda, Japan; 3: J-POWER Business Service Corporation, Chuo, Japan; 4: Yamaguchi University, Ube, JapanStrategy and application of slope monitoring over dam basin in regular periods and during emergencies using SAR and GNSSMonitoring the behavior of slopes around the sites of hydroelectric power plants and dam reservoirs over dam basins is important for their stable operation and a reduction in the risks of accidents and disasters. However, since there are numerous slopes widely located over a dam basin, it is generally not feasible to efficiently monitor the behavior of all the slopes over such an extensive area. Satellite technology, SAR and GNSS, will contribute to overcoming this difficulty. In the present paper, a strategy is proposed for slope monitoring over a dam basin in regular periods and during emergencies using SAR and GNSS. Then, practical applications are demonstrated for regularly monitoring the slopes and for detecting unstable slopes during an emergency brought about by an extremely heavy rainfall in Japan. | Monitoring, Slopes, Dam basin, SAR, GNSS
T10: MonitoringJune Ho PARK (1), Jin Seop KIM (2), Chang Ho HONG (2), Ji Won KIM (2), Tae Hyuk KWON (1)1: Korea Advanced Institute of Science and Technology, Daejeon, Republic of Korea; 2: Korea Atomic Energy Research Institute, Yuseong-gu, Daejeon, Republic of KoreaLow-frequency acoustic emission characteristics from meter-scale fracturing of rock-like brittle materialsThe acoustic emission (AE) method as a passive non-destructive monitoring technique is proposed for real-time monitoring of mechanical degradation in underground structures, such as deep geological disposal of high-level nuclear waste (HLW). This study investigates the low-frequency characteristics of AE signals emitted during fracturing of meter-scale concrete specimens. For comparison, uniaxial compression tests (UCT) and Goodman jack (GJ) tests in a 1.3 m-long concrete block were conducted while acquiring the AE signals using low-frequency AE sensors. The results showed that a sharp increase in AE energy emission occurred at ~60% and ~80% of the yield stresses in the UCT and GJ tests, respectively. High frequency AE signals were captured more as the tress increased in the GJ tests, which was in contrast to the UCT tests. The study presents unique experimental data with low-frequency AE sensors under different loading conditions, which provides insights into the field-scale AE monitoring practices. | Acoustic emission, low-frequency sensor, meter-scale, concrete, Goodman jack test
T10: MonitoringAlberto MICHELINIIDS GeoRadar, ItalyRegression analysis of slope instabilities evolution for time of failure estimationTime of failure (TOF) estimation of rock slope instabilities is one of the most important output of slope monitoring activities. Providing an accurate TOF estimation allows to significantly mitigate the risk associated with slope failure. Various kinematic models to describe the evolution of instabilities are available in literature, the most representative one is the hyperbolic evolution found by Saito. Different techniques have been proposed and used to fit the Saito model to the experimental data, among these, inverse velocity (IV) method and slope gradient (SLO) method are probably the most popular. However, with the recent development of near real-time monitoring systems, and with modern computing power, it is conceivable to approach the TOF estimation with powerful non-linear regression methods. In the present work, non-linear regression analysis of Saito's model is presented and tested on slope collapse datasets acquired from Ground-Based Synthetic Aperture Radar (GB-SAR) systems. | time of failure, failure forecasting, GB-SAR, slope stability, deformation monitoring
T10: MonitoringAdolf Bernd MORITZ (1), Johannes FLECKL (1), Werner LIENHART (2), Johann GOLSER (3), Thomas PILGERSTORFER (4)1: ÖBB-Infrastruktur AG, Graz, Austria; 2: Graz University of Technology, Austria; 3: Geodata, Leoben, Austria; 4: Geoconsult ZT GmbH, Puch bei Hallein, AustriaLong-term monitoring of Austrian railway tunnels – A next step forwardAt the large infrastructure projects of the Austrian Federal Railways OeBB in the Alpine region geotechnical structures with different characteristics are encountered. Especially fault zones associated with high overburden are a great challenge during tunnelling, often resulting in large deformation of the rock-support system. On the other hand support for tunnels in swelling ground has to be designed to an expected swelling pressure during the life time of a tunnel. The goal is to apply robust, reliable and durable monitoring systems for observing such geotechnical structures during a service life of the tunnels of 150 years. The benefit is to early detect unfavourable tendencies of the system behaviour and the planning of measures in terms of predictive maintenance accordingly in due time. Finally this ensures high availability of the tunnels during operation. The paper presents the implementation of long-term monitoring via the projects Koralm Tunnel, Granitztal Tunnel and the Semmering Base Tunnel. | long-term monitoring, OeBB railway tunnel, ground pressure, fibre optic sensing, vibrating wire strain sensors, automatic data acquisition
T10: MonitoringMartin ZIEGLER (1), Simon LOEW (1), Arash Alimardani LAVASAN (2), Ernando SARAIVA (3)1: Department of Earth Sciences, ETH Zurich, Switzerland; 2: Faculty of Civil and Environmental Engineering, Ruhr-Universität Bochum, Germany; 3: Swiss Federal Nuclear Safety InspectorateMonitoring long-term hydromechanical processes in swellable Opalinus Clay shale of the new Belchen tunnel (Switzerland)High swelling pressures and heaves of anhydrite-rich marls and Opalinus Clay shale (OPA) caused substantial damage to the Belchen highway tunnels between Basel and Lucerne in Switzerland, excavated with drill-and-blast technique in the 1960s. The tubes have to be refurbished and a new tunnel tube was constructed with a tunnel boring machine between 2016 and 2018. We have installed a monitoring system in a section of OPA to explore the evolution of radial pressures on the tunnel lining and the local hydro-mechanical conditions with the aim to characterize swelling processes of OPA in-situ. For the interpretation of radial pressures, the mechanical properties of the annular gap grout were explored and the impact of thermal strains on measured radial stresses was investigated with numerical simulations. Here we discuss key results obtained from the new Belchen tunnel that can be also relevant for design considerations of nuclear waste repositories in clay rocks. | Rock swelling, In-situ experiment, Swiss Jura mountains, THM coupled processes
T10: MonitoringCharlotte WOLFF (1), Tiggi CHOANJI (1), Marc-Henri DERRON (1), Li FEI (1), Michel JABOYEDOFF (1), Andrea PEDRAZZINI (2), Carlo RIVOLTA (3)1: ISTE - University of Lausanne, Lausanne, Switzerland; 2: Sezione forestale- Repubblica e Cantone Ticino, Bellinzona, Switzerland; 3: Ellegi Srl - operational and administrative headquarters, Milano, ItalyUse of combined monitoring remote sensing techniques for the study of active fractures in a remote area: Case of Cima Del Simano rockslideCima del Simano Mountain (Swiss Alps) presents one main open fracture and several smaller fractures. Satellite InSAR highlights downward movements. This instability is worthy to be studied since it represents a risk for the road and villages located at its foot. Nevertheless, this mountain is challenging to study because of its bad accessibility and the strong atmospheric effects on remote sensing techniques. The study combines remote sensing techniques to acquire a maximal amount of information on the potential rockfalls sources and slow deep-seated landslides. Those techniques are Lidar, satellite InSAR and Ground-Based InSAR (GB-InSAR). They are aimed at confirming failure scenarios, predicted based on structural analyses and field observations. Small toppling movements are detected as well as more long-term moving areas (few mm/year). We estimate the limits of those instabilities and their corresponding volume by applying the Slope Local Base Level (SLBL) method. | Rockslide, InSAR, LiDAR, monitoring, SLBL
T10: MonitoringTiggi CHOANJI (1,2), Li FEI (1), Charlotte WOLFF (1), Franck BOURRIER (3), Romain GAUCHER (4), Kan Jean KOUAMÉ (5), Marc-Henri DERRON (1), Michel JABOYEDOFF (1)1: Risk Group, ISTE, University of Lausanne, Geopolis – Quartier Mouline 1015 Lausanne, Switzerland; 2: Department of Geological Engineering, Islamic University of Riau, Pekanbaru Riau 28284, Indonesia; 3: Université Grenoble-Alpes, INRAE, ETNA, 38000 Grenoble, France; 4: Service Ingénierie, Département des Hautes-Alpes, Gap, Provence-Alpes-Côte d’Azur, France; 5: CURAT, Côte d’Ivoire, Bd. De l'Université, Université Félix HOUPHOUËT-BOIGNY d'Abidjan Cocody (Côte d'Ivoire)Rockfall simulation and identification their sources locations along Massive external crystalline in Alps zone using LiDAR and Panorama Images: Case of La Grave, FranceRockfall hazards are fundamental problems for roadway safety in hilly areas. Monitoring rockfall activity along the 17 km long road from Chambon to La Grave is necessary to assess frequency, return period, and magnitude of rockfall events. According to historical inventory, more than 15 rockfall occurred between 1999 and 2020. Therefore, annual LiDAR measurements, with a point density of 40 to 189 points/m2, and more than 10’000 images from high-resolution cameras are used for detecting and evaluating rockfalls. Based on comparisons between 2020 and 2021, three rockfall sources totalling 200 m3 have been identified. Rock stability is assessed by analysing topography to identify potential rockfall sources using slope angle distribution (SAD) analysis and overhanging slopes from point clouds. Then, the trajectory from each identified source was simulated and verified using historical rockfall data. Thus, this combination of techniques better identifies and predicts deposited rockfall and impacts on infrastructures. | Rockfall, LiDAR, Alpes, Rock stability
T10: MonitoringChristoph Martin MONSBERGER (1), Fabian BUCHMAYER (1), Werner LIENHART (1,2)1: ACI Monitoring GmbH, Austria; 2: Graz University of Technology, Institute of Engineering Geodesy and Measurement Systems, AustriaDistributed Fiber Optic Monitoring Systems in Tunneling: Implementation from research into practiceStructural monitoring in combination with reliable data interpretation is essential to understand the deformation behavior of the lining and finally, to guarantee safe construction and operation. Conventional techniques may involve limitations, either in the spatial or the temporal resolution and do not deliver the overall deformation behavior along the entire lining. Distributed fiber optic sensing (DFOS) has significantly evolved in recent years to monitor large scale civil infrastructure, with scientific sensing designs being realized within various research projects. The technology can be advantageous for in-situ tunnel monitoring since the distributed strain and temperature sensing feature delivers a complete picture of the linings’ structural deformation behavior without blind spots. This paper discusses numerous DFOS tunnel monitoring designs and realizations at different construction sites and demonstrates that fiber optic sensors have considerably developed and provide essential capabilities to extend the conventional, geotechnical monitoring toolkit. | Distributed fiber optic sensing, tunnel lining, field applications, deformation behavior, structural integrity monitoring