Pub Date : 2026-01-12DOI: 10.1016/j.ijrmms.2025.106396
Wei-Tong Li , Qi-Zhi Zhu , Wei-Jian Li , Xing-Guang Zhao
This paper presents an enhanced quasi-bond method for modeling mixed-mode fracture in rock-like materials. By integrating concepts from microplane theory, the proposed approach incorporates strain decomposition and projection onto bond directions, establishing bond-level stiffness through energy equivalence with classical elasticity. The formulation accommodates arbitrary Poisson’s ratios and preserves consistency across two-dimensional/three-dimensional settings. A novel dual-mechanism fracture criterion is introduced, incorporating both a bond-breakage rule based on energy thresholds and microstress states to differentiate tensile and shear cracks, and a complementary bond-level softening model that concurrently captures tensile and shear strength degradation. To improve numerical accuracy, a smoothed strain technique synchronizes strain updates with bond failure, and a hybrid finite element/quasi-bond coupling strategy enables efficient localized fracture resolution. Validations against notched beams and multi-flawed specimens under compression demonstrate the accuracy of the proposed model in solving mixed-mode fracture in rock-like materials. Engineering-scale extensions to jointed rock slopes reveal step-path fracture network evolution governed by flaw interaction-driven coalescence patterns, advancing geohazard predictions through explicit linkage between discrete fracturing and macro-scale instability.
{"title":"A microplane-enhanced quasi-bond method with a dual-mechanism fracture criterion for mixed-mode failure in rock-like materials","authors":"Wei-Tong Li , Qi-Zhi Zhu , Wei-Jian Li , Xing-Guang Zhao","doi":"10.1016/j.ijrmms.2025.106396","DOIUrl":"10.1016/j.ijrmms.2025.106396","url":null,"abstract":"<div><div>This paper presents an enhanced quasi-bond method for modeling mixed-mode fracture in rock-like materials. By integrating concepts from microplane theory, the proposed approach incorporates strain decomposition and projection onto bond directions, establishing bond-level stiffness through energy equivalence with classical elasticity. The formulation accommodates arbitrary Poisson’s ratios and preserves consistency across two-dimensional/three-dimensional settings. A novel dual-mechanism fracture criterion is introduced, incorporating both a bond-breakage rule based on energy thresholds and microstress states to differentiate tensile and shear cracks, and a complementary bond-level softening model that concurrently captures tensile and shear strength degradation. To improve numerical accuracy, a smoothed strain technique synchronizes strain updates with bond failure, and a hybrid finite element/quasi-bond coupling strategy enables efficient localized fracture resolution. Validations against notched beams and multi-flawed specimens under compression demonstrate the accuracy of the proposed model in solving mixed-mode fracture in rock-like materials. Engineering-scale extensions to jointed rock slopes reveal step-path fracture network evolution governed by flaw interaction-driven coalescence patterns, advancing geohazard predictions through explicit linkage between discrete fracturing and macro-scale instability.</div></div>","PeriodicalId":54941,"journal":{"name":"International Journal of Rock Mechanics and Mining Sciences","volume":"199 ","pages":"Article 106396"},"PeriodicalIF":7.5,"publicationDate":"2026-01-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145956879","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-10DOI: 10.1016/j.ijrmms.2026.106403
Jin-Hu Pan , Xiao-Ping Zhou
Understanding rockburst mechanism has always been a fundamental challenge in the field of geotechnical engineering. The nonlocal methods have excellent potential to simulate fragment problems such as rockburst. However, early researches employing nonlocal methods primarily focused on the static process of rockburst, their capabilities in simulating the full dynamic fracture propagation and fragment ejection processes remain to be further explored. To reproduce the dynamic rockburst process in deep tunnel, the present work proposes a novel nonlocal general particle dynamic method. Firstly, four types of contact behaviors in rockburst are identified and a contact model based on the theorem of momentum is proposed to determine the contact force. Secondly, we establish a joint model that distinguishes the tensile, compressive and shear deformation features of bonds to characterize the joints in rock masses. Thirdly, the Holmquist-Johnson-Cook constitutive model is modified to consider the features of high pressure and high strain rate in rockburst process and to simulate the damage evolution by incorporating the critical stretch criterion and critical equivalent strain criterion. The first three examples, oedometric test, block sliding on an inclined plane and wave propagation in a one-dimensional bar with a joint, are conducted to verify the proposed numerical framework. The final three examples simulate the rockburst phenomenon induced by excavation. The numerical results obtained by the developed approach are in high agreement with the experimental results and the field observations. The several typical features in rockburst, particle spalling, particle ejection and V-shaped rockburst pit, are successfully reproduced, which demonstrate that the proposed method possesses excellent ability to model the dynamic rockburst process and can provide a theoretical basis for hazard assessment and prevention strategies in deep underground engineering.
{"title":"Capturing dynamic rockburst behaviors of deep rock masses with a novel nonlocal general particle dynamic method","authors":"Jin-Hu Pan , Xiao-Ping Zhou","doi":"10.1016/j.ijrmms.2026.106403","DOIUrl":"10.1016/j.ijrmms.2026.106403","url":null,"abstract":"<div><div>Understanding rockburst mechanism has always been a fundamental challenge in the field of geotechnical engineering. The nonlocal methods have excellent potential to simulate fragment problems such as rockburst. However, early researches employing nonlocal methods primarily focused on the static process of rockburst, their capabilities in simulating the full dynamic fracture propagation and fragment ejection processes remain to be further explored. To reproduce the dynamic rockburst process in deep tunnel, the present work proposes a novel nonlocal general particle dynamic method. Firstly, four types of contact behaviors in rockburst are identified and a contact model based on the theorem of momentum is proposed to determine the contact force. Secondly, we establish a joint model that distinguishes the tensile, compressive and shear deformation features of bonds to characterize the joints in rock masses. Thirdly, the Holmquist-Johnson-Cook constitutive model is modified to consider the features of high pressure and high strain rate in rockburst process and to simulate the damage evolution by incorporating the critical stretch criterion and critical equivalent strain criterion. The first three examples, oedometric test, block sliding on an inclined plane and wave propagation in a one-dimensional bar with a joint, are conducted to verify the proposed numerical framework. The final three examples simulate the rockburst phenomenon induced by excavation. The numerical results obtained by the developed approach are in high agreement with the experimental results and the field observations. The several typical features in rockburst, particle spalling, particle ejection and V-shaped rockburst pit, are successfully reproduced, which demonstrate that the proposed method possesses excellent ability to model the dynamic rockburst process and can provide a theoretical basis for hazard assessment and prevention strategies in deep underground engineering.</div></div>","PeriodicalId":54941,"journal":{"name":"International Journal of Rock Mechanics and Mining Sciences","volume":"199 ","pages":"Article 106403"},"PeriodicalIF":7.5,"publicationDate":"2026-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145956889","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-09DOI: 10.1016/j.ijrmms.2025.106394
M.R. Hajiabadi, F. Amour, B. Hosseinzadeh, A.C. Cheriki, H. Nick
This study presents a multi-scale modelling framework to evaluate fault reactivation risks and seismic potential during CO2 injection into a highly depleted and deformable chalk reservoir, using the Harald East field in the northern part of the Danish North Sea as a case study. A robust multi-scale Thermo-Hydro-Mechanical (THM) modeling approach is developed to bridge field- and fault-scale processes, supporting fault stability and seismic risk assessment in CO2 storage. A field-scale coupled flow-geomechanical model is used to screen for critically-stressed faults, while fault-scale simulations investigate slip behaviour using a Mohr-Coulomb frictional model, combined with a rate-dependent frictional model to assess specific potential seismic events. THM analysis under realistic CO2 injection scenarios reveals that faults remain stable with friction coefficients of 0.6. However, simulations with reduced initial friction coefficients (e.g., 0.27 and 0.36) indicate localized slip risks during both production and injection phases along the plane of one single fault out of a total of 30 faults analysed. As the reservoir repressurizes, the stress regime transitions from normal to reverse faulting, accompanied by a significant reorientation in principal stress. This shift of stress regime causes a progressive rise in shear stress on the fault plane as repressurization continues, resulting in higher slip tendency values and a greater likelihood of seismic reactivation. Besides, the results demonstrate the benefit of a combined field- and fault-scale approach that enhances computational efficiency by restricting detailed analyses to critical faults and critical time throughout the injection period. This work provides a framework for fault stability and seismic risk assessments, offering key insights for the safe implementation of underground CO2 storage projects.
{"title":"Analysis of seismic potential in a depleted chalk reservoir subject to CO2 injection","authors":"M.R. Hajiabadi, F. Amour, B. Hosseinzadeh, A.C. Cheriki, H. Nick","doi":"10.1016/j.ijrmms.2025.106394","DOIUrl":"10.1016/j.ijrmms.2025.106394","url":null,"abstract":"<div><div>This study presents a multi-scale modelling framework to evaluate fault reactivation risks and seismic potential during CO<sub>2</sub> injection into a highly depleted and deformable chalk reservoir, using the Harald East field in the northern part of the Danish North Sea as a case study. A robust multi-scale Thermo-Hydro-Mechanical (THM) modeling approach is developed to bridge field- and fault-scale processes, supporting fault stability and seismic risk assessment in CO<sub>2</sub> storage. A field-scale coupled flow-geomechanical model is used to screen for critically-stressed faults, while fault-scale simulations investigate slip behaviour using a Mohr-Coulomb frictional model, combined with a rate-dependent frictional model to assess specific potential seismic events. THM analysis under realistic CO<sub>2</sub> injection scenarios reveals that faults remain stable with friction coefficients of 0.6. However, simulations with reduced initial friction coefficients (e.g., 0.27 and 0.36) indicate localized slip risks during both production and injection phases along the plane of one single fault out of a total of 30 faults analysed. As the reservoir repressurizes, the stress regime transitions from normal to reverse faulting, accompanied by a significant reorientation in principal stress. This shift of stress regime causes a progressive rise in shear stress on the fault plane as repressurization continues, resulting in higher slip tendency values and a greater likelihood of seismic reactivation. Besides, the results demonstrate the benefit of a combined field- and fault-scale approach that enhances computational efficiency by restricting detailed analyses to critical faults and critical time throughout the injection period. This work provides a framework for fault stability and seismic risk assessments, offering key insights for the safe implementation of underground CO<sub>2</sub> storage projects.</div></div>","PeriodicalId":54941,"journal":{"name":"International Journal of Rock Mechanics and Mining Sciences","volume":"199 ","pages":"Article 106394"},"PeriodicalIF":7.5,"publicationDate":"2026-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145941325","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-07DOI: 10.1016/j.ijrmms.2026.106400
Fengchang Bu , Ruoshen Lin , Michel Jaboyedoff , Wei Liu , Lei Xue
Despite widespread adoption of the bonded block model (BBM) in modelling intact rocks, the calibration of BBM modelling parameters remains a significant challenge, undermining the trustworthiness of BBM-simulated results. Existing trial-and-error and sensitivity analyses for calibration suffer from inefficiency, subjectivity, and difficulty in establishing the high-dimensional and nonlinear complex mapping from modelling parameters to modelled properties in BBM. To address this issue, built on BBM-based universal distinct element code (UDEC), we employed machine learning to clarify this complex mapping. A comprehensive numerical database with 3456 UDEC simulations was constructed for training machine learning models, followed by the selection of the optimal machine learning models by comparing their predictive performances. Subsequently, we collected experimental data from 99 rock types that served as modelled properties to be input into the selected trained machine learning models. Through an inversion by integrating grid search, the corresponding modelling parameters could be output, that is, the machine learning–calibrated modelling parameters. They were further imported into UDEC to perform another 1485 simulations to validate their reliability and robustness. It was also found that both lithology and block size affect calibration accuracy differently across modelled properties. In applying the framework, specific rock model configuration may be considered when establishing the numerical database, including the constitutive laws of blocks and contacts and specific rock structure. This study provides an effective solution for parametric calibration in BBM, advancing more reliable use of BBM in scientific and engineering contexts.
{"title":"Parametric calibration in bonded block models for simulating mechanical behaviours of intact rocks using machine learning","authors":"Fengchang Bu , Ruoshen Lin , Michel Jaboyedoff , Wei Liu , Lei Xue","doi":"10.1016/j.ijrmms.2026.106400","DOIUrl":"10.1016/j.ijrmms.2026.106400","url":null,"abstract":"<div><div>Despite widespread adoption of the bonded block model (BBM) in modelling intact rocks, the calibration of BBM modelling parameters remains a significant challenge, undermining the trustworthiness of BBM-simulated results. Existing trial-and-error and sensitivity analyses for calibration suffer from inefficiency, subjectivity, and difficulty in establishing the high-dimensional and nonlinear complex mapping from modelling parameters to modelled properties in BBM. To address this issue, built on BBM-based universal distinct element code (UDEC), we employed machine learning to clarify this complex mapping. A comprehensive numerical database with 3456 UDEC simulations was constructed for training machine learning models, followed by the selection of the optimal machine learning models by comparing their predictive performances. Subsequently, we collected experimental data from 99 rock types that served as modelled properties to be input into the selected trained machine learning models. Through an inversion by integrating grid search, the corresponding modelling parameters could be output, that is, the machine learning–calibrated modelling parameters. They were further imported into UDEC to perform another 1485 simulations to validate their reliability and robustness. It was also found that both lithology and block size affect calibration accuracy differently across modelled properties. In applying the framework, specific rock model configuration may be considered when establishing the numerical database, including the constitutive laws of blocks and contacts and specific rock structure. This study provides an effective solution for parametric calibration in BBM, advancing more reliable use of BBM in scientific and engineering contexts.</div></div>","PeriodicalId":54941,"journal":{"name":"International Journal of Rock Mechanics and Mining Sciences","volume":"199 ","pages":"Article 106400"},"PeriodicalIF":7.5,"publicationDate":"2026-01-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145908713","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Lined rock cavern (LRC) technology, known for its remarkable geographical flexibility, stands out as a promising and cost-effective approach to underground hydrogen storage. However, since these caverns are often built in complex geological settings and designed for prolonged operation, evaluating their long-term stability is crucial, which should take into account both the creep of rock masses under fatigue loading and the degradation of the steel lining under hydrogen embrittlement (HE). In this paper, we present a comprehensive numerical analysis of LRCs within fractured rock masses, incorporating the effects of time-dependent viscoelastic deformation in the host rock and HE processes in the steel lining under cyclic pressurization. A novel two-dimensional multiscale model is developed that captures the interactions between the LRC structure and the surrounding fractured rocks to assess the damage and degradation of concrete, rock, and steel components in the LRC system. Our framework uniquely integrates rock viscoelasticity and steel hydrogen embrittlement mechanisms, providing a quantitative means to evaluate the long-term mechanical–chemical interactions. The findings demonstrate that the rock’s viscoelastic behavior significantly impacts the time-dependent integrity of the LRC, with damage progressively accumulating during prolonged operation. Additionally, damage evolution in the concrete lining and rock mass, along with steel degradation, are strongly influenced by pre-existing fractures in the rock mass. While small relaxation times in the viscoelastic response lead to rapid system stabilization, moderate relaxation times can trigger time-dependent stress redistribution and further damage progression. The results also highlight the important effect of HE on LRC performance, especially when the surrounding rock mass is characterized by the presence of interconnected fractures. The insights gained in this study are critical to optimizing the design and ensuring the long-term safe operation of LRCs in the context of sustainable underground hydrogen storage.
{"title":"Influence of rock creep on the performance of lined caverns under cyclic pressurization and hydrogen embrittlement","authors":"Chenxi Zhao , Haiyang Yu , Zixin Zhang , Qinghua Lei","doi":"10.1016/j.ijrmms.2026.106401","DOIUrl":"10.1016/j.ijrmms.2026.106401","url":null,"abstract":"<div><div>Lined rock cavern (LRC) technology, known for its remarkable geographical flexibility, stands out as a promising and cost-effective approach to underground hydrogen storage. However, since these caverns are often built in complex geological settings and designed for prolonged operation, evaluating their long-term stability is crucial, which should take into account both the creep of rock masses under fatigue loading and the degradation of the steel lining under hydrogen embrittlement (HE). In this paper, we present a comprehensive numerical analysis of LRCs within fractured rock masses, incorporating the effects of time-dependent viscoelastic deformation in the host rock and HE processes in the steel lining under cyclic pressurization. A novel two-dimensional multiscale model is developed that captures the interactions between the LRC structure and the surrounding fractured rocks to assess the damage and degradation of concrete, rock, and steel components in the LRC system. Our framework uniquely integrates rock viscoelasticity and steel hydrogen embrittlement mechanisms, providing a quantitative means to evaluate the long-term mechanical–chemical interactions. The findings demonstrate that the rock’s viscoelastic behavior significantly impacts the time-dependent integrity of the LRC, with damage progressively accumulating during prolonged operation. Additionally, damage evolution in the concrete lining and rock mass, along with steel degradation, are strongly influenced by pre-existing fractures in the rock mass. While small relaxation times in the viscoelastic response lead to rapid system stabilization, moderate relaxation times can trigger time-dependent stress redistribution and further damage progression. The results also highlight the important effect of HE on LRC performance, especially when the surrounding rock mass is characterized by the presence of interconnected fractures. The insights gained in this study are critical to optimizing the design and ensuring the long-term safe operation of LRCs in the context of sustainable underground hydrogen storage.</div></div>","PeriodicalId":54941,"journal":{"name":"International Journal of Rock Mechanics and Mining Sciences","volume":"199 ","pages":"Article 106401"},"PeriodicalIF":7.5,"publicationDate":"2026-01-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145908712","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-07DOI: 10.1016/j.ijrmms.2026.106399
Youn-Kyou Lee , S. Pietruszczak
The elastic behavior of transversely isotropic rocks is governed by five independent constants. Conventional methods for measuring these elastic constants typically involve uniaxial compression tests on three specimens sampled at different inclinations with respect to the isotropy plane. However, this approach may introduce errors due to specimen heterogeneity. In this study, three sets of simple inversion formulas are derived to determine five elastic constants from strain data obtained during hydrostatic compression followed by an increment of axial stress applied to a single inclined specimen. Each of these three sets includes an identical equation for the shear modulus and a distinct matrix equation for the remaining four elastic constants. Although these matrix equations differ in appearance, they are mathematically equivalent and yield identical solutions. To facilitate coordinate transformation, the Mehrabadi-Cowin notation was employed, in which the strain and stress states are represented as first-order tensors in a six-dimensional space, and the corresponding compliance matrix is treated as a second-order tensor in the same space. The input data for the proposed inversion formulas consist of strain measurements taken in a coordinate system aligned with the strike and dip directions of the isotropy plane. If the orientation of the isotropy plane can be inferred from the strain data, then strain measurements obtained in an arbitrary coordinate system can also be used as input. Illustrative examples are provided to demonstrate the accuracy and practical relevance of the proposed approach.
{"title":"Identification of elastic constants of transversely isotropic rocks using strain measurements from a single inclined specimen","authors":"Youn-Kyou Lee , S. Pietruszczak","doi":"10.1016/j.ijrmms.2026.106399","DOIUrl":"10.1016/j.ijrmms.2026.106399","url":null,"abstract":"<div><div>The elastic behavior of transversely isotropic rocks is governed by five independent constants. Conventional methods for measuring these elastic constants typically involve uniaxial compression tests on three specimens sampled at different inclinations with respect to the isotropy plane. However, this approach may introduce errors due to specimen heterogeneity. In this study, three sets of simple inversion formulas are derived to determine five elastic constants from strain data obtained during hydrostatic compression followed by an increment of axial stress applied to a single inclined specimen. Each of these three sets includes an identical equation for the shear modulus and a distinct matrix equation for the remaining four elastic constants. Although these matrix equations differ in appearance, they are mathematically equivalent and yield identical solutions. To facilitate coordinate transformation, the Mehrabadi-Cowin notation was employed, in which the strain and stress states are represented as first-order tensors in a six-dimensional space, and the corresponding compliance matrix is treated as a second-order tensor in the same space. The input data for the proposed inversion formulas consist of strain measurements taken in a coordinate system aligned with the strike and dip directions of the isotropy plane. If the orientation of the isotropy plane can be inferred from the strain data, then strain measurements obtained in an arbitrary coordinate system can also be used as input. Illustrative examples are provided to demonstrate the accuracy and practical relevance of the proposed approach.</div></div>","PeriodicalId":54941,"journal":{"name":"International Journal of Rock Mechanics and Mining Sciences","volume":"199 ","pages":"Article 106399"},"PeriodicalIF":7.5,"publicationDate":"2026-01-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145908711","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-02DOI: 10.1016/j.ijrmms.2025.106387
Bruce Gee , Mengsu Hu , Michael Manga
Deep geologic repositories are a proposed solution to dispose of nuclear waste at the end of its useful life. The radioactive decay of the contents inside the waste canisters releases heat into the repository near- and far-field environments that drives coupled heat transport, fluid transport, and stress development in the rock mass. The degree of coupling between processes and the corresponding temperature, pressure, and stress distributions can change significantly depending on the rock mass parameters. Not all coupled processes are simultaneously active and analysis time and effort can be reduced through a proper selection of relevant mechanisms. Here we use a combination of scaling analysis and numerical simulations to map the solutions across parameter space and establish dominant coupled processes regimes. We find that permeability has the greatest effect on the regimes. Pressure exhibits three regimes: an undrained regime at low permeability, transitioning to a drained regime, then a buoyant regime. Stress has two regimes: an undrained regime transitioning to a drained regime. Temperature has three regimes: conduction, advection, and buoyant convection. Conduction is dominant across most expected permeabilities, while the advection dominant regime only occurs at high permeability and is only expected in highly fractured rock masses. Analytical criteria to predict the transition from the drained to buoyant pressure regimes and the conductive to advective temperature regimes are derived and verified against the numerical simulations. The establishment of dominant process regimes allows for a reduction in computational time and complexity and enables more efficient analysis and design of nuclear waste repositories.
{"title":"Timescales and solution regimes for heat driven thermo–poro–mechanical processes in geologic nuclear waste disposal","authors":"Bruce Gee , Mengsu Hu , Michael Manga","doi":"10.1016/j.ijrmms.2025.106387","DOIUrl":"10.1016/j.ijrmms.2025.106387","url":null,"abstract":"<div><div>Deep geologic repositories are a proposed solution to dispose of nuclear waste at the end of its useful life. The radioactive decay of the contents inside the waste canisters releases heat into the repository near- and far-field environments that drives coupled heat transport, fluid transport, and stress development in the rock mass. The degree of coupling between processes and the corresponding temperature, pressure, and stress distributions can change significantly depending on the rock mass parameters. Not all coupled processes are simultaneously active and analysis time and effort can be reduced through a proper selection of relevant mechanisms. Here we use a combination of scaling analysis and numerical simulations to map the solutions across parameter space and establish dominant coupled processes regimes. We find that permeability has the greatest effect on the regimes. Pressure exhibits three regimes: an undrained regime at low permeability, transitioning to a drained regime, then a buoyant regime. Stress has two regimes: an undrained regime transitioning to a drained regime. Temperature has three regimes: conduction, advection, and buoyant convection. Conduction is dominant across most expected permeabilities, while the advection dominant regime only occurs at high permeability and is only expected in highly fractured rock masses. Analytical criteria to predict the transition from the drained to buoyant pressure regimes and the conductive to advective temperature regimes are derived and verified against the numerical simulations. The establishment of dominant process regimes allows for a reduction in computational time and complexity and enables more efficient analysis and design of nuclear waste repositories.</div></div>","PeriodicalId":54941,"journal":{"name":"International Journal of Rock Mechanics and Mining Sciences","volume":"198 ","pages":"Article 106387"},"PeriodicalIF":7.5,"publicationDate":"2026-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145884407","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-01DOI: 10.1016/j.ijrmms.2025.106392
Shaofeng Wang , Xinlei Shi , Yu Tang , Xin Cai , Zilong Zhou , Shanyong Wang
Non-explosive mechanized rock breaking technology is being increasingly adopted for deep rock excavation. The complexity of stress conditions in deep rock can significantly affect the efficiency of non-explosive mechanized rock breaking. However, the limited understanding of the rock breaking performance of conical picks under complex stress conditions constrains the application of this technique in deep rock engineering projects. In this study, the rock breaking characteristics associated with rock indentation under varying confining stress levels were investigated through numerical simulations using discrete element modelling software (MatDEM). The results indicate that tensile fractures predominantly occur during vertical indentation. As the confining stress increases, the length and quantity of radial cracks generated within the rock decrease. When the confining stress exceeds 9 MPa (16.6 % of the uniaxial compressive strength of rock), discrete distributions of tensile cracks form within the rock during the indentation process. Moreover, the evolution of rock energy exhibits a nonlinear double-peak trend with increasing confining stress, whereas the system heat evolution demonstrates a “decrease–increase–decrease” pattern. Additionally, the rock cuttability is evaluated by analysing the indentation force and specific energy during the initial leap process. The findings reveal that the rock is more easily fractured under low- or no-stress conditions. As the confining stress increases, the rock cuttability initially decreases but subsequently increases. This study reveals the nonlinear mechanism of confining stress on controlling crack propagation and energy evolution during rock indentation, providing a theoretical basis and technical pathway for non-explosive mechanized mining in deep hard rock.
{"title":"Effects of confining stress on crack propagation and energy evolution during rock indentation: Insights from 2D-DEM simulations and implications for mechanized mining","authors":"Shaofeng Wang , Xinlei Shi , Yu Tang , Xin Cai , Zilong Zhou , Shanyong Wang","doi":"10.1016/j.ijrmms.2025.106392","DOIUrl":"10.1016/j.ijrmms.2025.106392","url":null,"abstract":"<div><div>Non-explosive mechanized rock breaking technology is being increasingly adopted for deep rock excavation. The complexity of stress conditions in deep rock can significantly affect the efficiency of non-explosive mechanized rock breaking. However, the limited understanding of the rock breaking performance of conical picks under complex stress conditions constrains the application of this technique in deep rock engineering projects. In this study, the rock breaking characteristics associated with rock indentation under varying confining stress levels were investigated through numerical simulations using discrete element modelling software (MatDEM). The results indicate that tensile fractures predominantly occur during vertical indentation. As the confining stress increases, the length and quantity of radial cracks generated within the rock decrease. When the confining stress exceeds 9 MPa (16.6 % of the uniaxial compressive strength of rock), discrete distributions of tensile cracks form within the rock during the indentation process. Moreover, the evolution of rock energy exhibits a nonlinear double-peak trend with increasing confining stress, whereas the system heat evolution demonstrates a “decrease–increase–decrease” pattern. Additionally, the rock cuttability is evaluated by analysing the indentation force and specific energy during the initial leap process. The findings reveal that the rock is more easily fractured under low- or no-stress conditions. As the confining stress increases, the rock cuttability initially decreases but subsequently increases. This study reveals the nonlinear mechanism of confining stress on controlling crack propagation and energy evolution during rock indentation, providing a theoretical basis and technical pathway for non-explosive mechanized mining in deep hard rock.</div></div>","PeriodicalId":54941,"journal":{"name":"International Journal of Rock Mechanics and Mining Sciences","volume":"198 ","pages":"Article 106392"},"PeriodicalIF":7.5,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145884406","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-31DOI: 10.1016/j.ijrmms.2025.106393
Bin Chen , Qiaojie Shu , Quanlin Zhou , Yuan Wang , Hui Wu
Cold fluid injection in various subsurface applications may induce thermal fracturing, which is a coupled process of fracture propagation, heat conduction and convection, and fluid flow in the fractures and reservoir. While most existing studies employ a thermoelastic model, their accuracy may be compromised by thermoporoelastic effects. This study aims to systematically investigate the thermoporoelastic effects in thermal fracturing using numerical models of varying complexity. We first developed a fully coupled model incorporating all relevant physical processes including fracture propagation and arrest, heat and fluid transport in fractures and reservoir. A novel dimensionless framework with five key parameters is introduced to elucidate the thermo-hydro-mechanical coupling. Additionally, three partially coupled models are developed to isolate the effects of diffusion- and deformation-induced back stress, pore water contraction, and heat convection. Extensive numerical simulations indicate that (1) diffusion-induced back stress minimally impedes the fracture propagation in case of nonnegligible permeability and pressure differential, (2) deformation-induced back stress and pore water contraction primarily affect fracture growth in low-permeability rock, reducing and increasing fracture length by 3.81 %–18.61 % and 15.51 %–49.99 %, respectively, under undrained condition, (3) heat convection is the dominant thermoporoelastic effect under high permeability and pressure differential, significantly promoting fracture propagation, and (4) thermoporoelastic effects have negligible influence on thermal fracturing for permeability between 10−18 m2 and 10−15 m2.
{"title":"Fundamental insights into thermoporoelastic effects in thermal fracturing induced by cold fluid injection","authors":"Bin Chen , Qiaojie Shu , Quanlin Zhou , Yuan Wang , Hui Wu","doi":"10.1016/j.ijrmms.2025.106393","DOIUrl":"10.1016/j.ijrmms.2025.106393","url":null,"abstract":"<div><div>Cold fluid injection in various subsurface applications may induce thermal fracturing, which is a coupled process of fracture propagation, heat conduction and convection, and fluid flow in the fractures and reservoir. While most existing studies employ a thermoelastic model, their accuracy may be compromised by thermoporoelastic effects. This study aims to systematically investigate the thermoporoelastic effects in thermal fracturing using numerical models of varying complexity. We first developed a fully coupled model incorporating all relevant physical processes including fracture propagation and arrest, heat and fluid transport in fractures and reservoir. A novel dimensionless framework with five key parameters is introduced to elucidate the thermo-hydro-mechanical coupling. Additionally, three partially coupled models are developed to isolate the effects of diffusion- and deformation-induced back stress, pore water contraction, and heat convection. Extensive numerical simulations indicate that (1) <em>diffusion-induced back stress</em> minimally impedes the fracture propagation in case of nonnegligible permeability and pressure differential, (2) <em>deformation-induced back stress</em> and <em>pore water contraction</em> primarily affect fracture growth in low-permeability rock, reducing and increasing fracture length by 3.81 %–18.61 % and 15.51 %–49.99 %, respectively, under undrained condition, (3) <em>heat convection</em> is the dominant thermoporoelastic effect under high permeability and pressure differential, significantly promoting fracture propagation, and (4) thermoporoelastic effects have negligible influence on thermal fracturing for permeability between 10<sup>−18</sup> m<sup>2</sup> and 10<sup>−15</sup> m<sup>2</sup>.</div></div>","PeriodicalId":54941,"journal":{"name":"International Journal of Rock Mechanics and Mining Sciences","volume":"198 ","pages":"Article 106393"},"PeriodicalIF":7.5,"publicationDate":"2025-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145884359","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-29DOI: 10.1016/j.ijrmms.2025.106377
Dapeng Wang , Haojun Wang , Yaolan Tang , Haoyu Shi , Jianchun Li , Jian Zhao
Understanding the seismic response and energy release of fault surfaces under impact disturbances is crucial for predicting and assessing the risk of induced seismicity. This study utilized a biaxial Hopkinson bar system to conduct direct shear experiments on simulated faults with different interlocking segment characteristics, aiming to investigate the influence of fault surface morphology and pre-stress on seismic response and energy release. High-speed three-dimensional digital image correlation (3D-DIC) and rock CT were employed for qualitative and quantitative observations of dynamic deformation and failure characteristics. Experimental results indicate that fault surfaces with different morphological characteristics exhibited three types of seismic responses under varying initial normal stresses: climb, cut, and climb accompanied by fracture. The fracture consistently initiated at the teeth and subsequently propagated, exhibiting pronounced unilateral rupture characteristics. Under impact disturbance, both normal and shear strains exhibited a bell-shaped spatial distribution centered on the simulated fault surface, reflecting strong strain localization. This distribution was effectively characterized using a generalized Gaussian fitting framework, with the extracted shape parameters providing quantitative metrics for localized deformation behavior. The peak dynamic shear strength increased with both undulation angle and teeth number and positively correlated with initial normal stress. However, the friction coefficient did not show a strictly monotonic increasing trend. A fixed proportional relationship was observed between normal and shear strain during dynamic disturbance, varying based on loading conditions and fault surface characteristics. This relationship allows for a simplified calculation of the energy released from the simulated fault under dynamic disturbances. This research further clarifies the asperity-controlled seismic response and quantifies the strain-energy distribution induced by impact disturbances, offering valuable insights for assessing and monitoring induced seismic hazards under sudden dynamic loading.
{"title":"Seismic response and energy release of simulated faults with varying morphology and pre-stress under impact disturbance","authors":"Dapeng Wang , Haojun Wang , Yaolan Tang , Haoyu Shi , Jianchun Li , Jian Zhao","doi":"10.1016/j.ijrmms.2025.106377","DOIUrl":"10.1016/j.ijrmms.2025.106377","url":null,"abstract":"<div><div>Understanding the seismic response and energy release of fault surfaces under impact disturbances is crucial for predicting and assessing the risk of induced seismicity. This study utilized a biaxial Hopkinson bar system to conduct direct shear experiments on simulated faults with different interlocking segment characteristics, aiming to investigate the influence of fault surface morphology and pre-stress on seismic response and energy release. High-speed three-dimensional digital image correlation (3D-DIC) and rock CT were employed for qualitative and quantitative observations of dynamic deformation and failure characteristics. Experimental results indicate that fault surfaces with different morphological characteristics exhibited three types of seismic responses under varying initial normal stresses: climb, cut, and climb accompanied by fracture. The fracture consistently initiated at the teeth and subsequently propagated, exhibiting pronounced unilateral rupture characteristics. Under impact disturbance, both normal and shear strains exhibited a bell-shaped spatial distribution centered on the simulated fault surface, reflecting strong strain localization. This distribution was effectively characterized using a generalized Gaussian fitting framework, with the extracted shape parameters providing quantitative metrics for localized deformation behavior. The peak dynamic shear strength increased with both undulation angle and teeth number and positively correlated with initial normal stress. However, the friction coefficient did not show a strictly monotonic increasing trend. A fixed proportional relationship was observed between normal and shear strain during dynamic disturbance, varying based on loading conditions and fault surface characteristics. This relationship allows for a simplified calculation of the energy released from the simulated fault under dynamic disturbances. This research further clarifies the asperity-controlled seismic response and quantifies the strain-energy distribution induced by impact disturbances, offering valuable insights for assessing and monitoring induced seismic hazards under sudden dynamic loading.</div></div>","PeriodicalId":54941,"journal":{"name":"International Journal of Rock Mechanics and Mining Sciences","volume":"198 ","pages":"Article 106377"},"PeriodicalIF":7.5,"publicationDate":"2025-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145884361","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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