Geomechanics for Energy and the Environment最新文献

{"title":"Coupled hydro-gas-mechanical 3D modeling of LASGIT experiment","authors":"B.S. Noghretab ,&nbsp;I.P. Damians ,&nbsp;S. Olivella ,&nbsp;A. Gens","doi":"10.1016/j.gete.2024.100623","DOIUrl":"10.1016/j.gete.2024.100623","url":null,"abstract":"<div><div>Gas transport simulation in bentonite for radioactive waste disposal poses challenges for numerical models due to its complex microstructure. Understanding the processes involved is a prerequisite for assessing gas flow's impact on repository layouts. The DECOVALEX23 (D-2023) Task B (Large Scale Gas Injection Test: LASGIT) project aims to advance numerical techniques for predicting gas flow in repository systems through gas injection tests on compacted bentonite at the British Geological Survey (BGS). This study develops a comprehensive coupled hydro-gas-mechanical 3D numerical model to simulate the test, considering heterogeneous initial permeability and embedded fractures. Addressing bentonite swelling, three gap closure scenarios for the canister-bentonite blocks gap interface were considered. The model reproduces observed test behaviors, capturing preferential gas flow paths. Sensitivity analysis explores variations in volume factor sensitivity, calibration, hydraulic conductivity of interfaces, heterogeneity, permeability, and model parameters, contributing to a deeper understanding of the phenomenon's complexity. The proposed hydraulic modeling, enriched by considerations of gap closure states, predicts measured evolution of gas injection trends. suggesting reliability and potential applicability for similar conditions and facilitating a comprehensive analysis of its impact on gas testing processes. Additionally, the embedded fracture models underscore the critical role of fracture behavior and dilatancy in determining the system's hydro-mechanical response, with significant sensitivity to these factors influencing stress and pore pressure evolution. Hydro-mechanical models demonstrate that modeling approaches involving embedded fractures and dilatancy significantly influence gas pathways and entry gas pressure. System volume plays pivotal role in the analysis, while sensitivity analysis of contact transmissivity reveals potential influences on preferential gas pathway formation. Hydraulic and hydro-mechanical modeling methods show promise for further numerical investigations, indicating potential for yielding meaningful insights in future studies.</div></div>","PeriodicalId":56008,"journal":{"name":"Geomechanics for Energy and the Environment","volume":"40 ","pages":"Article 100623"},"PeriodicalIF":3.3,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143164652","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Hybrid framework for surrogate modelling of massive solar collectors in road pavements","authors":"Taher Ghalandari ,&nbsp;David M.G. Taborda ,&nbsp;Alalea Kia ,&nbsp;Cedric Vuye","doi":"10.1016/j.gete.2024.100617","DOIUrl":"10.1016/j.gete.2024.100617","url":null,"abstract":"<div><div>This paper investigates the application of surrogate modelling in the design and thermal response assessment of Pavement Solar Collectors (PSCs). The PSC system is a sustainable infrastructure solution that utilises both solar and shallow geothermal energy. PSCs incorporate a network of pipes embedded in the asphalt layer to create a heat exchange layer. During warm months, water circulating through this layer captures solar heat, which can then be used for snow melting in winter, enhancing road safety, or for domestic and industrial heating applications. Finite Element (FE) analysis is a widely used method for evaluating the thermal response of PSCs to optimize their design. However, the substantial computational requirements of numerical modelling, especially for long-term time-dependent analyses, pose significant challenges in assessing the long-term thermal behaviour of PSCs. Surrogate models, approximating complex physics-based simulations, drastically reduce computational demands, enabling rapid and accurate evaluations of various design parameters and scenarios. In this study, a validated FE simulation framework was employed to generate data, which was then used to develop a data-driven surrogate model for PSCs. In order to refine the surrogate model's performance to its optimal level, hyperparameter optimisation was carried out. The comparison of outlet water temperature results between finite element and surrogate models showed a high correlation, with a coefficient of determination of 0.97 observed for both training and test data sets. Subsequently, the surrogate model was integrated as an objective function in a Particle Swarm Optimization (PSO) algorithm to automate the Heat Harvesting Capacity (HHC) optimisation of PSCs. The PSO algorithm demonstrates robust performance in identifying optimal solutions while also offering a substantial reduction in computational costs compared to FE simulations.</div></div>","PeriodicalId":56008,"journal":{"name":"Geomechanics for Energy and the Environment","volume":"40 ","pages":"Article 100617"},"PeriodicalIF":3.3,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142743894","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Comparing modelling approaches for a generic nuclear waste repository in salt","authors":"Tara LaForce ,&nbsp;Jeroen Bartol ,&nbsp;Dirk-Alexander Becker ,&nbsp;Steven Benbow ,&nbsp;Alexander Bond ,&nbsp;Carl Rudolf Dietl ,&nbsp;Tanja Frank ,&nbsp;Ingo Kock ,&nbsp;Fabiano Magri ,&nbsp;Josh Nicholas ,&nbsp;Rick Jayne ,&nbsp;Marek Pekala ,&nbsp;Philip H. Stauffer ,&nbsp;Emily Stein ,&nbsp;Jodie Stone ,&nbsp;Jens Wolf","doi":"10.1016/j.gete.2024.100621","DOIUrl":"10.1016/j.gete.2024.100621","url":null,"abstract":"<div><div>This paper contains a comparison of five modelling approaches for a simplified nuclear waste repository in a domal salt formation. It is the result of a four-year collaboration between five international teams on Task F of the DECOVALEX-2023 project on performance assessment modelling. The primary objectives of Task F are to build confidence in the models, methods, and software used for performance assessment (PA) of deep geologic nuclear waste repositories, and/or to bring to the fore additional research and development needed to improve PA methodologies. This work demonstrates how these objectives are accomplished through staged development and comparison of the models and methods used by participating teams in their PA frameworks. Participating teams made a wide range of model assumptions, ranging from compartmentalized networks to full 3D models of the salt formation and repository. Despite differences in the modelling strategies, all models indicate that salt compaction and diffusion of radionuclides in brine are key processes in the repository. For the isothermal spent nuclear fuel and vitrified waste scenario with multiple early failures considered, all models indicate little of the disposed radionuclides will migrate beyond the repository seal over the 100,000-year simulations. In general, the model output quantities have the largest differences over the short term and near the waste. Disparities between the models are believed to be due to differing simplifications from the conceptual model.</div></div>","PeriodicalId":56008,"journal":{"name":"Geomechanics for Energy and the Environment","volume":"40 ","pages":"Article 100621"},"PeriodicalIF":3.3,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143164651","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"In situ static elastic properties assessment and validation with pressuremeter testing using a formation tester tool","authors":"Jean E. Elkhoury ,&nbsp;Thomas Bérard ,&nbsp;Jean Desroches ,&nbsp;Emilie Peyret ,&nbsp;Romain Prioul ,&nbsp;Eleonora Crisci ,&nbsp;Rodney Garrard ,&nbsp;Silvio B. Giger","doi":"10.1016/j.gete.2024.100619","DOIUrl":"10.1016/j.gete.2024.100619","url":null,"abstract":"<div><div>Pressuremeter testing (PMT) is a formation test that consists of inflating a cylindrical packer inside a borehole while measuring the radial deformation or injected fluid volume as a function of packer pressure. Provided that the stiffness of the packer measuring system is known and large enough compared to that of the formation, changes in packer pressure associated with changes in injected fluid volume provide a direct measurement of formation stiffness. In turn, the in situ static shear modulus is obtained from the formation stiffness at a length scale similar to that of the packer. Here, we report on the first field-scale campaign of PMTs in deep boreholes performed using a wireline formation tester (WFT) tool. We carried out PMT measurements as part of the characterization and appraisal of potential sites for a deep geological repository for radioactive waste in Switzerland. We performed multiple PMT inflation cycles to infer in situ static shear moduli at six stations spread across four boreholes. PMT-derived static shear moduli results were consistent with static shear moduli derived from sonic logs using independent dynamic-to-static elastic moduli transformations. PMT-derived static shear moduli and laboratory-derived static elastic moduli using samples from coring performed at the depths of the PMT stations were consistent, with slightly lower laboratory values. Furthermore, we report dynamic-to-static shear moduli transformations by using laboratory-scale data obtained on cores and field-scale derived from sonic logs and PMT. We observed differences between static and dynamic shear moduli derived from laboratory scale using cores and field scale using sonic logs and PMT. We report linear trend slopes of about 0.5 for the laboratory data and 0.7 for the field data. These first results show the viability of in situ PMT in deep boreholes with a WFT tool, as it can be performed at multiple depths in a single run, in a time-efficient manner, and in combination with micro-hydraulic and sleeve fracturing stress tests for an integral approach to in situ geomechanical assessment.</div></div>","PeriodicalId":56008,"journal":{"name":"Geomechanics for Energy and the Environment","volume":"40 ","pages":"Article 100619"},"PeriodicalIF":3.3,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143164577","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Influence of mechanical strength on gas migration through bentonite: Numerical analysis from laboratory to field scale","authors":"Jung-Tae Kim ,&nbsp;Changsoo Lee ,&nbsp;Minhyeong Lee ,&nbsp;Jin-Seop Kim ,&nbsp;E. Tamayo-Mas ,&nbsp;J.F. Harrington","doi":"10.1016/j.gete.2024.100614","DOIUrl":"10.1016/j.gete.2024.100614","url":null,"abstract":"<div><div>Understanding the gas movement phenomenon within the deep geological repository is essential for assessing the disposal system’s long-term stability. The primary gas transport mechanism through the bentonite is dilatancy-controlled flow, which differs from gas flow in general porous media. This flow is characterized by gas movement through microcracks created under relatively high gas pressure conditions, and the intrinsic permeability, air-entry pressure, and mechanical strength of the medium change due to the generation and propagation of these microcracks. Therefore, dilatancy-controlled flow cannot be simulated using the classical two-phase flow modeling technique. This study constructed the H<span><math><msup><mrow></mrow><mrow><mn>2</mn></mrow></msup></math></span>MD (two-phase hydraulic-mechanical-damage) numerical model by combining a damage model to simulate material degradation and the resulting change in intrinsic permeability with a classical two-phase flow model. In addition, the numerical model was tested against a 1D laboratory gas injection test investing gas flow mechanisms in the buffer, and a sensitivity analysis was performed on tensile strength, a key factor in the damage model for gas movement phenomenon. In the validation study, the proposed model successfully simulated the key features observed in the test: rapid stress and pressure increase trends, changes in intrinsic permeability due to damage, and the resulting flow rate. In addition, the effect of heterogeneity on the strength characteristics of each material and interfaces between materials was analyzed through field-scale test simulations, and the applicability of the model to upscaling analysis was examined. The study of heterogeneity effects confirmed that incorporating the strength characteristics of interfaces accurately simulates the gas flow path observed in actual tests. However, the model overestimated the gas flow before the gas breakthrough and underestimated the evolution of the damaged area within the buffer. Therefore, additional research on relative permeability and mechanical constitutive models is needed to improve the reliability of the current model.</div></div>","PeriodicalId":56008,"journal":{"name":"Geomechanics for Energy and the Environment","volume":"40 ","pages":"Article 100614"},"PeriodicalIF":3.3,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143164650","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Functional analysis of the constitutive role of temperature in compacted bentonites","authors":"Vicente Navarro ,&nbsp;Gema Urraca ,&nbsp;Laura Asensio","doi":"10.1016/j.gete.2024.100620","DOIUrl":"10.1016/j.gete.2024.100620","url":null,"abstract":"<div><div>A thermodynamically consistent expression is derived for the functional structure of effective stress understood as the work conjugate of elastic strain. The study, focussed on compacted clays, is valid for both non-isothermal conditions and constant temperature. As a result, it is found that there is no evidence to assume a direct dependence of the effective stress on temperature. Therefore, it is consistent to follow the usually employed strategies based on evaluating the implicit dependence through air pressure, macrostructural liquid pressure and macrostructural degree of saturation.</div></div>","PeriodicalId":56008,"journal":{"name":"Geomechanics for Energy and the Environment","volume":"40 ","pages":"Article 100620"},"PeriodicalIF":3.3,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142743895","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Numerical modeling of hydro-mechanical processes during hydraulic testing of pre-existing fractures at the Grimsel Test Site, Switzerland","authors":"Josselin Ouf ,&nbsp;Kavan Khaledi ,&nbsp;Philip J. Vardon ,&nbsp;Wen Luo ,&nbsp;Mohammadreza Jalali ,&nbsp;Florian Amann","doi":"10.1016/j.gete.2024.100608","DOIUrl":"10.1016/j.gete.2024.100608","url":null,"abstract":"<div><div>This study presents a fully coupled hydro-mechanical framework for modeling hydraulic shearing in a mesoscale reservoir located at the Grimsel Test Site, Switzerland. The experiment was conducted on a ductile–brittle fault embedded in low-permeable granite. We observe that normal fracture opening increases flow channel recoverably, while fracture sliding locks asperities leading to a non-recoverable increase in flow. To couple these processes, we use a poro-elasto-plastic constitutive framework and employ a permeability function that depends on several parameters, such as dilation angle, in-situ stresses, residual aperture and maximum aperture. Our results capture the recorded pressure responses well, and indicate that the permeability changes by one order of magnitude during the experiment.</div></div>","PeriodicalId":56008,"journal":{"name":"Geomechanics for Energy and the Environment","volume":"40 ","pages":"Article 100608"},"PeriodicalIF":3.3,"publicationDate":"2024-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142651374","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Comparison between new enhanced thermal response test methods for underground heat exchanger sizing","authors":"A. Galgaro ,&nbsp;R. Da Re ,&nbsp;A. Carrera ,&nbsp;E. Di Sipio ,&nbsp;G. Dalla Santa","doi":"10.1016/j.gete.2024.100613","DOIUrl":"10.1016/j.gete.2024.100613","url":null,"abstract":"<div><div>For the efficient design and implementation of a Ground Source Heat Pump (GSHP) system, the local subsoil stands as the core element. Alongside the conventional Thermal Response Test (TRT), recent research has developed improved approaches that garner more detailed information about ground thermal properties. One such technique is the fiber optic-based distributed thermal sensing. It relies on copper wires to thermally stimulate the ground, while optical fibers collect temperature variations over time along the cable. Another pioneering technology, the enhanced GEOsniff (produced by enOware GmbH), enables high-resolution, spatially-distributed representation of subsoil thermal properties along the Borehole Heat Exchanger (BHE) via wireless data transmission. This study compares and discusses data acquired through these two innovative techniques at the new campus for the humanities of the University of Padova, situated in Northern Italy's Eastern Po river plain. The findings are further juxtaposed with conventional TRT results, in terms of thermal conductivity and borehole thermal resistance. The thermal conductivity vertical profiles are also compared with direct measurements conducted on samples. These advanced techniques show promise in aiding the optimization of borehole length design, particularly in geological settings of heightened complexity.</div></div>","PeriodicalId":56008,"journal":{"name":"Geomechanics for Energy and the Environment","volume":"40 ","pages":"Article 100613"},"PeriodicalIF":3.3,"publicationDate":"2024-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142650683","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Early and post-stage piping erosion in bentonite buffer materials exposed to groundwater inflow","authors":"Minhyeong Lee ,&nbsp;Chang-Ho Hong ,&nbsp;Ji-Won Kim ,&nbsp;Jinwoo Kim ,&nbsp;Jin-Seop Kim","doi":"10.1016/j.gete.2024.100611","DOIUrl":"10.1016/j.gete.2024.100611","url":null,"abstract":"<div><div>Piping erosion presents a significant concern in engineered barrier system (EBS), contributing to performance uncertainties. However, the early-stage hydration and piping erosion characteristics of calcium-type bentonite under concentrated water inflow conditions are not fully understood. To address this gap, we examined early- and post-stage piping erosion in bentonite buffer materials. Specifically, we focused on the onset and evolution of piping channels with changes in the inflow pressure and their impact on buffer material integrity. Piping experiments were conducted using bentonite in block, granule, and powder forms under constant flow rate conditions. We analyzed the hydraulic-mechanical responses at the bentonite-cell interface, fluctuations in inflow water pressure, and eroded soil mass. Additionally, X-ray computed tomography imaging was utilized to assess the deterioration of buffer materials after piping. The results revealed that early-stage hydration-induced erosion behaviors are contingent upon the state of the bentonite buffer, with compacted blocks exhibiting predominant piping erosion. The rapid pressure buildup and breakthrough is essential in triggering piping erosion in the blocks, while the evolution of piping channels is influenced by the flow rate. Furthermore, severe cracks occurred along with the piping channels under reduced flow rate conditions, creating voids in the buffer amounting to 1.5–3.1 % of its initial volume. These findings provide insights into buffer-rock interfacial interactions in EBS, serving as the basis for in situ disposal experiments and the safe design of disposal repositories.</div></div>","PeriodicalId":56008,"journal":{"name":"Geomechanics for Energy and the Environment","volume":"40 ","pages":"Article 100611"},"PeriodicalIF":3.3,"publicationDate":"2024-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142535955","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Dam impoundment near active faults in areas with high seismic potential: Case studies from Bisri and Mseilha dams, Lebanon","authors":"A. Yehya ,&nbsp;J. Basbous ,&nbsp;E. Maalouf ,&nbsp;T.S. Nemer","doi":"10.1016/j.gete.2024.100610","DOIUrl":"10.1016/j.gete.2024.100610","url":null,"abstract":"<div><div>Reservoir induced seismicity is caused by stress changes due to the impoundment of water behind dams. In seismically active areas, the presence of critically located active faults makes the impoundment of water behind dams a seismic safety risk. Dam projects in Lebanon have become a soaring example of complacency and negligence that has overlooked the concerns for seismic safety raised over the projects and their high potential of inducing seismicity. In this paper, we use 2D and 3D fully coupled poroelastic modeling to assess the risk of dam impoundment on seismogenic faults located near dam sites in Lebanon. The coulomb failure stresses are calculated along the faults, and their variations are observed in relation to changes in pore pressures and normal stresses. In addition, the expected maximum earthquake magnitudes are computed along those faults. Our results show a high risk for reservoir induced seismicity on faults that are either underneath the reservoir or hydraulically connected to a fault beneath the reservoir. Consequently, the studied dams would present a serious hazard of induced seismicity in time where the region is already at high risk of destructive earthquakes after the catastrophic seismic events that struck Turkey and Syria on 6 February 2023 on the Eastern Anatolian Fault, which is connected to the Dead Sea Transform Fault that passes through Lebanon.</div></div>","PeriodicalId":56008,"journal":{"name":"Geomechanics for Energy and the Environment","volume":"40 ","pages":"Article 100610"},"PeriodicalIF":3.3,"publicationDate":"2024-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142535953","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}