Geomechanics for Energy and the Environment最新文献

{"title":"Creep properties and model of fractured sandstone under freezing environment","authors":"Yongxin Che ,&nbsp;Yongjun Song ,&nbsp;Huimin Yang ,&nbsp;Xixi Guo","doi":"10.1016/j.gete.2024.100554","DOIUrl":"10.1016/j.gete.2024.100554","url":null,"abstract":"<div><p>Creep is an important mechanical property of fractured rock. To explore the creep mechanical properties and damage evolution law of surrounding rock mass under long-term external load during freezing construction, triaxial graded loading creep and CT tests are conducted under a freezing environment (−10 °C) on sandstone with different fracture dip angles. The test results reveal that the prefabricated fracture have a significant impact on the creep of sandstone under freezing environment. As the fracture dip angel increases, the creep duration, creep deformation, and long-term strength all decrease first and then increase, with lower values at 15° and 45°. At 0°、 15° and 45° dip angles, the rocks exhibit integrated shear through failure, whereas rocks with a dip angle of 75° and 90° exhibit the mode of tensile shear through failure. Notably, no microcracks or secondary cracks are observed in the rock samples. Finally, a nonlinear viscoelastic–plastic constitutive model of fractured sandstone is established via fractional calculus. Fitting the experimental curve with the theoretical model reveals that the proposed creep damage model could accurately describe the creep behavior of fractured sandstone under freezing, especially in the accelerated creep stage, which validates the reliability of the parameters.</p></div>","PeriodicalId":56008,"journal":{"name":"Geomechanics for Energy and the Environment","volume":"38 ","pages":"Article 100554"},"PeriodicalIF":5.1,"publicationDate":"2024-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140278071","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":"Fractional derivative modelling for consolidation of multilayered saturated soils with interfacial thermal contact resistance subjected to time-dependent heating and loading","authors":"Kejie Tang,&nbsp;Minjie Wen,&nbsp;Pan Ding,&nbsp;Yiming Zhang,&nbsp;Yuan Tu,&nbsp;Jiahao Xie,&nbsp;Kaifu Liu,&nbsp;Dazhi Wu","doi":"10.1016/j.gete.2024.100553","DOIUrl":"https://doi.org/10.1016/j.gete.2024.100553","url":null,"abstract":"<div><p>In this paper, the one-dimensional rheological consolidation characteristics of multilayered saturated soil foundations under time-dependent loading and heating are investigated by considering the semi-permeability and the interface thermal resistance. By introducing the fractional derivative model and the thermos-elastic theory, a thermo-mechanical coupling model is established to describe the rheological properties of saturated soils. Semi-analytical solutions for strain, temperature increment, pore water pressure and settlement were derived through the Laplace transform and its inverse. The accuracy of the solutions proposed in this paper has been verified by comparing with existing solutions. The effects of different thermal contact models of the interface on the rheological properties of saturated soils under semi-permeable boundary are discussed, and the effects of fractional derivative order, constitutive material parameters, and thermal conductivity of soil on the thermal consolidation process are investigated. The results show that: neglecting the thermal resistance effect can result in an overestimates of the impact of rheological properties on the thermal consolidation process of saturated soils under semi-permeable boundaries; As the thermal resistance coefficient increases, the influence of soil thermal conductivity on settlement decreases.</p></div>","PeriodicalId":56008,"journal":{"name":"Geomechanics for Energy and the Environment","volume":"38 ","pages":"Article 100553"},"PeriodicalIF":5.1,"publicationDate":"2024-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140296573","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":"Modelling a gas injection experiment incorporating embedded fractures and heterogeneous material properties","authors":"Alfonso Rodriguez-Dono ,&nbsp;Yunfeng Zhou ,&nbsp;Sebastia Olivella ,&nbsp;Antonio Gens","doi":"10.1016/j.gete.2024.100552","DOIUrl":"10.1016/j.gete.2024.100552","url":null,"abstract":"<div><p>This study focuses on the modelling of a gas injection experiment to assess the effects of incorporating heterogeneous material properties. The numerical model considers a two-phase flow coupled hydro-mechanical problem, and includes embedded fractures that open with deformation, thereby enhancing permeability. The approach used is integrated in the CODE_BRIGHT software, which allows for the consideration of geomaterials with a spatially correlated heterogeneous field of porosity that follows a normal distribution. This spatial correlation can be either isotropic or anisotropic. A key aspect of this approach is that material properties such as intrinsic permeability, diffusivity or cohesion are defined as a function of porosity. Consequently, these properties also exhibit heterogeneity with spatial correlation and, eventually, anisotropy. The results derived from the numerical model align well with in-situ measurements. The study also includes sensitivity analyses to the variation of critical variables. The calibration of the model has been validated through a similar experiment. The findings indicate that the consideration of heterogeneous material properties can have a significant influence on gas injection problems, particularly when a hydraulic fracture is formed.</p></div>","PeriodicalId":56008,"journal":{"name":"Geomechanics for Energy and the Environment","volume":"38 ","pages":"Article 100552"},"PeriodicalIF":5.1,"publicationDate":"2024-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2352380824000194/pdfft?md5=c57dc4678c38bfef1c3ccfbac4bc8709&pid=1-s2.0-S2352380824000194-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140273475","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":"Slip-weakening friction controls coseismic displacements in a 3D fracture network: Implications for the long-term safety of nuclear waste repositories","authors":"Wenbo Pan ,&nbsp;Zixin Zhang ,&nbsp;Shuaifeng Wang ,&nbsp;Qinghua Lei","doi":"10.1016/j.gete.2024.100551","DOIUrl":"https://doi.org/10.1016/j.gete.2024.100551","url":null,"abstract":"<div><p>During the long-term operational lifespan of nuclear waste repositories in crystalline rock formations, large earthquakes along nearby seismogenic fault zones may occur, coseismically triggering shear displacements of secondary fractures within the respository site. In addition, these secondary fractures that may be associated with slip-weakening friction could accommodate significant slip instabilities and large shear displacements. A cumulative shear displacement exceeding 50 mm could affect the integrity of waste canisters, potentially resulting in the escape of hazardous radionuclides into the groundwater system. To investigate this problem, we develop a novel 3D seismo-mechanical model to simulate the transient rupture of a primary seismogenic fault zone and coseismic slips in a network of secondary fractures located around the primary fault. A plausible postglacial earthquake scenario is studied, where the rupture along the seismogenic fault propagates outward from a predefined hypocenter, with the resulting static stress changes and dynamic ground vibrations captured. We explore different cases with secondary fractures having different degrees of slip-weakening friction, which is found to strongly control the spatial decay of coseismic fracture displacements in the system. The findings derived from our study have significant implications for assessing the long-term safety of nuclear waste repositories in faulted and fractured crystalline rocks.</p></div>","PeriodicalId":56008,"journal":{"name":"Geomechanics for Energy and the Environment","volume":"38 ","pages":"Article 100551"},"PeriodicalIF":5.1,"publicationDate":"2024-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140190969","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":"Numerical modeling of the fracturing mechanisms of unconsolidated sand reservoirs under water injection","authors":"Ana Carolina Loyola ,&nbsp;Jean Sulem ,&nbsp;Jean-Claude Dupla ,&nbsp;Jalel Ochi","doi":"10.1016/j.gete.2024.100550","DOIUrl":"https://doi.org/10.1016/j.gete.2024.100550","url":null,"abstract":"<div><p>Produced Water Re-Injection is a standard practice in oil and gas operations. When performed at sufficiently high pressures, it can trigger the fracturing of the reservoir, which should be controlled to stimulate the formation without compromising its safety. While the mechanisms of the hydraulic fracturing of brittle rocks are well-understood, this understanding is more challenging in the case of unconsolidated sand reservoirs. Recent experimental studies indicate that pseudofractures in such formations primarily result from shear banding and flow channelization. There is a need for further interpretation of the experimental findings through numerical models that account for the proper physical phenomena. For that, a coupled finite element model of water percolation, particle transport and strain localization is developed to replicate the experiments of radial injection of water in mixtures of sand and fines by Nguyen et al., 2022: <em>An experimental setup with radial injection cell for investigation of fracturing in unconsolidated sand reservoirs under fluid injection. Journal of Petroleum Science and Engineering 213:11036</em>. To simulate shear banding, the model accounts for strain-softening behavior and introduces material imperfections in a few weak elements. Particle mobilization starts once a critical fluid velocity is reached and permeability is assumed to be a function of particle concentration. The numerical models can replicate the geometry of the observed radial pseudofractures, as well as the measured fracturing pressures. They also qualitatively capture the effects of the initial stress state on the fracturing pressure, the fracture length and on the permeability increases during the fracturing regime as observed in the laboratory tests. Notably, the numerical results gave hints on the role of the coupling between strain localization and particle transport on the formation of the pseudofractures. These findings are used to propose an updated conceptual model for the hydraulic fracturing of sand packs.</p></div>","PeriodicalId":56008,"journal":{"name":"Geomechanics for Energy and the Environment","volume":"38 ","pages":"Article 100550"},"PeriodicalIF":5.1,"publicationDate":"2024-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2352380824000170/pdfft?md5=0a352678dfb5dfed99e2527e0fcab433&pid=1-s2.0-S2352380824000170-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140134028","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":"Assessment of mechanical behavior and failure criteria under varied confining pressures in treated calcareous sand","authors":"Jianxiao Gu ,&nbsp;Haibo Lyu ,&nbsp;Bo Li ,&nbsp;Hui Chen ,&nbsp;Xiaojiang Xu ,&nbsp;Xinyu Du","doi":"10.1016/j.gete.2024.100548","DOIUrl":"10.1016/j.gete.2024.100548","url":null,"abstract":"<div><p>Ensuring project safety for maritime geotechnical structures primarily composed of calcareous sand is crucial. Cement-based reinforcement is a promising strategy to enhance integrity and deformability, especially for overlying infrastructures in high-pressure ocean engineering. Firstly, the specimens are created by blending Portland cement and Gypsum into calcareous sand at contents of 16% and 22% and then subjected to curing periods of 7 and 3 days to explore their resistance to loading. Secondly, a triaxial consolidated drained test is conducted, applying different confining pressures ranging from 100 to 1200 kPa. This test aims to assess the mechanical behavior, strength parameters, failure criteria, and stress dilatancy behaviors of treated specimen. The results illustrating the peak shear strength points of all treated specimens display a concave nonlinear shape sloping downwards. An equation is presented to modify the mean effective stress and accommodate the influence of bonding strength. Finally, A revised criterion is formulated by integrating this equation into the failure criterion. Significantly, this refined failure criterion accurately defines the failure envelopes. An equation was established to reveal the relationship between the brittleness index and confining pressure. Additionally, two stress ratio parameters are defined based on the brittleness index to describe bonding degradation comprehensively.</p></div>","PeriodicalId":56008,"journal":{"name":"Geomechanics for Energy and the Environment","volume":"38 ","pages":"Article 100548"},"PeriodicalIF":5.1,"publicationDate":"2024-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140097846","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":"A micro-mechanical insight into the thermo-mechanical behaviour of clays","authors":"Alice Di Donna ,&nbsp;Angela Casarella ,&nbsp;Alessandro Tarantino","doi":"10.1016/j.gete.2024.100549","DOIUrl":"10.1016/j.gete.2024.100549","url":null,"abstract":"<div><p>The response of fine-grained soils to the combined effects of stress and temperature is a problem of growing concern in geoenvironmental engineering. Unlike most materials, fine-grained soils subjected to heating under drained conditions can exhibit either reversible expansion or irreversible contraction, depending on their loading history. This clay complex thermo-mechanical behaviour is widely reported in the literature, but its origin is still unknown. This paper explores the particle-scale origin of clay thermo-mechanical behaviour and helps to inform constitutive thermo-mechanical models. Clay particle interactions include non-contact forces, which are electrochemical in nature and prevail in face-to-face configuration and contact forces, which are mechanical forces transferred from one particle to another through a contact surface, typical of edge-to-face configuration. Non-contact forces include electrostatic Coulombic forces and van der Waals attractive forces. This paper proposes a combined numerical and analytical approach to quantify the elementary interactions between clay particles. The results are used to interpret typical stress-thermal paths, such as compression tests at different temperatures and heating-cooling cycles at constant mechanical stress. It is concluded that the electrochemical interactions governing the face-to-face particle configuration can only explain the elastic volumetric response of over-consolidated clays subjected to heating. The thermo-plastic behaviour associated with the reduction of the pre-consolidation pressure with temperature and the volumetric plastic compressive strain in response to heating in normally-consolidated clays is attributed to the edge-to-face particle configurations.</p></div>","PeriodicalId":56008,"journal":{"name":"Geomechanics for Energy and the Environment","volume":"38 ","pages":"Article 100549"},"PeriodicalIF":5.1,"publicationDate":"2024-03-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140033778","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":"Modelling of failure and fracture development of the Callovo-Oxfordian claystone during an in-situ heating experiment associated with geological disposal of high-level radioactive waste","authors":"Tsubasa Sasaki,&nbsp;Sangcheol Yoon,&nbsp;Jonny Rutqvist","doi":"10.1016/j.gete.2024.100546","DOIUrl":"10.1016/j.gete.2024.100546","url":null,"abstract":"<div><p>To ensure the safety of geological disposal of high-level radioactive waste, in-situ experiments have been carried out to examine the behavior of rocks in underground research laboratories (URLs). At the Meuse/Haute-Marne URL in France, the French National Radioactive Waste Management Agency (Andra) has been assessing the Callovo-Oxfordian claystone (COx) as potential host rock of geological disposal by subjecting the COx to in-situ heating mimicking exothermic radioactive waste. Results of the in-situ experiments are used to validate and bolster the numerical simulators for predicting the thermo-hydromechanically (THM) coupled behavior of the COx. The numerical simulators are, however, yet to be tested for predicting the failure and fracture development of the COx during heating, which is of paramount importance to the safety of the geological disposal. In this research, we modelled a recently carried out in-situ experiment at the Meuse/Haute-Marne URL using the TOUGH-FLAC simulator to predict the failure and fracture development of the COx during heating. The objectives are to examine the effects of (i) the weak bedding planes, (ii) the softening rate of matrix/weak plane strengths, and (iii) the stiffness anisotropy of the COx on the development of shear and tensile fractures during heating. Results show that considering failure along the weak planes enabled accurate predictions of fracture development. Also, fracture development intensified at a softening rate beyond a threshold level and the geometry of fractures was significantly affected by the stiffness anisotropy. These results will help boost the reliability of the safety and performance assessment of geological disposal in claystone.</p></div>","PeriodicalId":56008,"journal":{"name":"Geomechanics for Energy and the Environment","volume":"38 ","pages":"Article 100546"},"PeriodicalIF":5.1,"publicationDate":"2024-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2352380824000133/pdfft?md5=09690d33b6c8a660ce58ea3ba55cd9e6&pid=1-s2.0-S2352380824000133-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140033662","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":"Insight into the mechanical degradation of coal corroded by concentrated brine solution","authors":"Haiyang Yi ,&nbsp;Zhenxing Ji ,&nbsp;Jianfeng Liu ,&nbsp;Zhuang Zhuo ,&nbsp;Sihai Yi ,&nbsp;Xianfeng Shi","doi":"10.1016/j.gete.2024.100547","DOIUrl":"10.1016/j.gete.2024.100547","url":null,"abstract":"<div><p>Underground water reservoirs (UWR) of coal mine plays a significant role in enhancing the ecological environment and safeguarding water resources. The water stored in UWR, known as brine solution, seriously damages the mechanical properties of the coal pillar. However, the mechanical degradation characteristics of coal under the action of different concentration solutions are still unclear. In this paper, we propose a novel coal corrosion device to simulate the real environment, designed to ensure the effective dissolution of the solution to the samples. Here we show the results of brine solution corrosion tests, considering ion composition changes, microscopic CT imaging, and mechanical properties. The solution ion composition experiences significant changes after the corrosion test. The variation in <span><math><mrow><mi>M</mi><msup><mrow><mi>n</mi></mrow><mrow><mn>2</mn><mo>+</mo></mrow></msup></mrow></math></span> ion content can reflect the reaction degree and trend of water–rock interaction; CT test visually demonstrates the microstructural changes, allowing for direct observation of dissolution, generation, and attachment phenomena. The specimen’s overall porosity increases after corrosion; Triaxial compression tests were conducted, and both solution concentration and corrosion time can cause varying degrees of mechanical parameters degradation. Our results demonstrate how solution concentration affects coal and the extent of its impact. We anticipate our research will contribute to the construction and long-term safety of UWR.</p></div>","PeriodicalId":56008,"journal":{"name":"Geomechanics for Energy and the Environment","volume":"38 ","pages":"Article 100547"},"PeriodicalIF":5.1,"publicationDate":"2024-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140033754","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":"Rock-mass heterogeneous rheological properties caused the formation of deep tension fractures","authors":"Guoqing Chen ,&nbsp;Xiang Sun ,&nbsp;Qiang Xu ,&nbsp;Sihong Zeng ,&nbsp;Jingfang Xing ,&nbsp;Xuemin Feng ,&nbsp;Fangzhou Liu","doi":"10.1016/j.gete.2024.100545","DOIUrl":"https://doi.org/10.1016/j.gete.2024.100545","url":null,"abstract":"<div><p>Tension failure is a unique phenomenon in solid Earth that occurs on scales ranging from large plate rift valleys to small laboratory rocks. On a slope scale, deep unloading tension fractures are distinct from conventional unloading fractures and are a unique geological phenomenon in valleys with high in-situ stress. To accurately reproduce the development and evolution of deep unloading tension fractures and to support major excavation projects, a series of works including geological investigation, laboratory tests, intrinsic model establishment, and numerical simulation were carried out in this study. The unloading rheological tests, accounting for time-dependent effects, uncover the heterogeneity in the rheological attributes of rock-mass strength parameters during valley downcutting. This heterogeneity manifests as a transition in rock-mass strength parameters that cohesion weakening-friction strengthening (CWFS). Drawing on the results of laboratory tests, a novel viscoelastic-plastic model, termed the WSR model, was proposed. This model takes into account both CWFS and rheological considerations. It has been applied to simulate deep unloading tension fractures in the Jinping I hydropower station (JP-I) and compared with conventional models. The results show that WSR model accurately reproduced the development and evolution of deep unloading tension fractures and the heterogeneity of rock-mass deformation during age evolution leads to the formation of deep unloading tension fractures. In this study, the rock-mass heterogeneous rheological properties were summarized as the heterogeneity of the rock-mass strength parameters during age deterioration and the heterogeneity of rock-mass deformation during age evolution; the WSR model was proposed to characterize the heterogeneous rheological property of rock-mass strength parameters and to reproduce the development and evolution of deep unloading tension fractures in the JP-I. This novel contribution to deep unloading tension fractures emphasizes that the rock-mass heterogeneous rheological properties lead to the formation of deep unloading tension fractures.</p></div>","PeriodicalId":56008,"journal":{"name":"Geomechanics for Energy and the Environment","volume":"38 ","pages":"Article 100545"},"PeriodicalIF":5.1,"publicationDate":"2024-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140014602","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}