Xinxin Nie, Qian Yin, Zhigang Tao, Minghui Ren, Jiangyu Wu, Bo Meng, Zhaobo Li, Yaoyao Meng
The long‐term stability of roadside backfill structures in deep coal mining is critically threatened by complex static‐dynamic combined loads, yet the multiscale fatigue damage mechanisms remain elusive. This study aims to elucidate the nonlinear mechanical responses and damage evolution of backfill materials by establishing a high‐fidelity 3D discrete element model that integrates micro‐CT scanning reconstruction with a nonlinear parallel‐bonded stress corrosion (NPSC) model. The simulation results indicate that the proposed framework accurately reproduces the hysteresis curve characteristics and irreversible strain accumulation, with peak strength prediction errors controlled within 0.08% ∼ 4.31%. A critical dynamic amplitude threshold of 4 ∼ 5 MPa was identified, exceeding this limit triggers a transition from stable two‐stage damage accumulation to accelerated three‐stage failure. Mesoscopic analysis reveals that fatigue cracks preferentially initiate at weak matrix‐aggregate interfaces and propagate to dismantle the aggregate–aggregate load‐bearing skeleton. Additionally, the coupling effect of high static pre‐load was found to significantly promote crack propagation, thereby diminishing the material's safety margin against subsequent dynamic disturbances. These findings provide theoretical support for optimizing mining intensity and support strategies to enhance the durability of deep underground infrastructure.
{"title":"Nonlinear Mechanical Responses and Fatigue Damage Mechanisms of Roadside Backfill Materials Under Static‐dynamic Combined Loads","authors":"Xinxin Nie, Qian Yin, Zhigang Tao, Minghui Ren, Jiangyu Wu, Bo Meng, Zhaobo Li, Yaoyao Meng","doi":"10.1002/nag.70267","DOIUrl":"https://doi.org/10.1002/nag.70267","url":null,"abstract":"The long‐term stability of roadside backfill structures in deep coal mining is critically threatened by complex static‐dynamic combined loads, yet the multiscale fatigue damage mechanisms remain elusive. This study aims to elucidate the nonlinear mechanical responses and damage evolution of backfill materials by establishing a high‐fidelity 3D discrete element model that integrates micro‐CT scanning reconstruction with a nonlinear parallel‐bonded stress corrosion (NPSC) model. The simulation results indicate that the proposed framework accurately reproduces the hysteresis curve characteristics and irreversible strain accumulation, with peak strength prediction errors controlled within 0.08% ∼ 4.31%. A critical dynamic amplitude threshold of 4 ∼ 5 MPa was identified, exceeding this limit triggers a transition from stable two‐stage damage accumulation to accelerated three‐stage failure. Mesoscopic analysis reveals that fatigue cracks preferentially initiate at weak matrix‐aggregate interfaces and propagate to dismantle the aggregate–aggregate load‐bearing skeleton. Additionally, the coupling effect of high static pre‐load was found to significantly promote crack propagation, thereby diminishing the material's safety margin against subsequent dynamic disturbances. These findings provide theoretical support for optimizing mining intensity and support strategies to enhance the durability of deep underground infrastructure.","PeriodicalId":13786,"journal":{"name":"International Journal for Numerical and Analytical Methods in Geomechanics","volume":"1 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2026-02-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146145953","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}
Ground deformation induced by pore‐pressure dissipation poses significant challenges for geotechnical stability, yet traditional numerical solvers for Biot's consolidation often suffer from high computational cost and poor convergence, while standard PINNs struggle with gradient competition, inadequate spatial correlation modeling, and insufficient high‐order derivative accuracy. To address these limitations, this study proposes AGM‐PINNs, a novel framework that integrates a graph‐attention‐based spatiotemporal alignment module, an adaptive wavelet activation function (AWAF), and a mixture‐of‐experts (MoE) optimizer to efficiently solve three‐dimensional Biot's consolidation problems. The graph attention mechanism dynamically focuses on high‐gradient regions such as seepage fronts and stress concentration zones; AWAF enhances numerical smoothness and derivative fidelity; and MoE adaptively balances the multiphysics residuals to mitigate gradient competition. Extensive numerical experiments, including 1D, 2D, and 3D benchmarks, demonstrate that AGM‐PINNs achieve training losses on the order of , reduce displacement prediction errors from 8.954 mm in standard PINNs to 0.205 mm, and accurately infer permeability parameters with an average absolute error of . These results highlight the framework's robustness, high accuracy, and strong applicability to complex, multiscale hydro‐mechanical coupling problems, offering a reliable and mesh‐free computational tool for practical geotechnical engineering.
{"title":"A Physics‐Informed Deep Learning Framework for Multi‐Field Hydro‐Mechanical Consolidation Analysis","authors":"Erxuan Cai, Zhiran Gao, Zhexi Xu, Songqing Zuo, Minjie Wen, Yiming Zhang","doi":"10.1002/nag.70260","DOIUrl":"https://doi.org/10.1002/nag.70260","url":null,"abstract":"Ground deformation induced by pore‐pressure dissipation poses significant challenges for geotechnical stability, yet traditional numerical solvers for Biot's consolidation often suffer from high computational cost and poor convergence, while standard PINNs struggle with gradient competition, inadequate spatial correlation modeling, and insufficient high‐order derivative accuracy. To address these limitations, this study proposes AGM‐PINNs, a novel framework that integrates a graph‐attention‐based spatiotemporal alignment module, an adaptive wavelet activation function (AWAF), and a mixture‐of‐experts (MoE) optimizer to efficiently solve three‐dimensional Biot's consolidation problems. The graph attention mechanism dynamically focuses on high‐gradient regions such as seepage fronts and stress concentration zones; AWAF enhances numerical smoothness and derivative fidelity; and MoE adaptively balances the multiphysics residuals to mitigate gradient competition. Extensive numerical experiments, including 1D, 2D, and 3D benchmarks, demonstrate that AGM‐PINNs achieve training losses on the order of , reduce displacement prediction errors from 8.954 mm in standard PINNs to 0.205 mm, and accurately infer permeability parameters with an average absolute error of . These results highlight the framework's robustness, high accuracy, and strong applicability to complex, multiscale hydro‐mechanical coupling problems, offering a reliable and mesh‐free computational tool for practical geotechnical engineering.","PeriodicalId":13786,"journal":{"name":"International Journal for Numerical and Analytical Methods in Geomechanics","volume":"241 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2026-02-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146122028","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}
Accurately grasping the law of gas occurrence is of vital importance for the prevention and control of coal and gas outbursts. Traditional methods have problems such as low identification accuracy and insufficient predictability. Therefore, this study constructed a gas diffusion‐seepage fluid‐solid coupling model that can reflect the non‐homogeneity of coal matrix pores, and combined it with a calculation model of gas desorption from coal chips during dynamic drilling. The characteristics of gas emission during the entire process of dynamic coal breaking by drilling were studied through COMSOL numerical simulation. The research results were verified on‐site using a self‐developed intrinsically safe wireless multiparameter gas detector for mining. The gas emission laws under different initial gas pressures, overburden loads, and drilling speeds were analyzed. It was found that the gas emission rate rose sharply at the beginning of coal breaking and then quickly stabilized, while the cumulative emission volume increased linearly. The initial gas pressure was positively correlated with the emission volume and emission rate. The overburden load suppressed gas emission by compressing pores, and there was a marginal effect. Increasing the drilling speed reduced the cumulative emission volume but increased the instantaneous peak rate. Based on the analysis of the laws, a multifactor relationship model of cumulative gas emission from the borehole during dynamic coal breaking with the initial gas pressure, overburden load, drilling speed, and hole depth was established. The determination coefficient R2 of the model fitted by multiple linear regression was 0.996, with a small prediction error. It is suitable for engineering estimation and trend analysis, providing a new method for the advanced identification of gas abnormal zones.
{"title":"Research on Gas Emission Characteristics During Dynamic Coal Breaking in Boreholes Based on Bidisperse Diffusion Model and Coal Dust Desorption Calculation Model: Under Different Original Gas Pressures and Overburden Loads","authors":"Zhenxing Zhou, Gongda Wang, Haiyan Wang, Huiyong Niu, Yikang Liu, Xiaolu Liu","doi":"10.1002/nag.70266","DOIUrl":"https://doi.org/10.1002/nag.70266","url":null,"abstract":"Accurately grasping the law of gas occurrence is of vital importance for the prevention and control of coal and gas outbursts. Traditional methods have problems such as low identification accuracy and insufficient predictability. Therefore, this study constructed a gas diffusion‐seepage fluid‐solid coupling model that can reflect the non‐homogeneity of coal matrix pores, and combined it with a calculation model of gas desorption from coal chips during dynamic drilling. The characteristics of gas emission during the entire process of dynamic coal breaking by drilling were studied through COMSOL numerical simulation. The research results were verified on‐site using a self‐developed intrinsically safe wireless multiparameter gas detector for mining. The gas emission laws under different initial gas pressures, overburden loads, and drilling speeds were analyzed. It was found that the gas emission rate rose sharply at the beginning of coal breaking and then quickly stabilized, while the cumulative emission volume increased linearly. The initial gas pressure was positively correlated with the emission volume and emission rate. The overburden load suppressed gas emission by compressing pores, and there was a marginal effect. Increasing the drilling speed reduced the cumulative emission volume but increased the instantaneous peak rate. Based on the analysis of the laws, a multifactor relationship model of cumulative gas emission from the borehole during dynamic coal breaking with the initial gas pressure, overburden load, drilling speed, and hole depth was established. The determination coefficient <jats:italic>R</jats:italic> <jats:sup>2</jats:sup> of the model fitted by multiple linear regression was 0.996, with a small prediction error. It is suitable for engineering estimation and trend analysis, providing a new method for the advanced identification of gas abnormal zones.","PeriodicalId":13786,"journal":{"name":"International Journal for Numerical and Analytical Methods in Geomechanics","volume":"15 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2026-02-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146122031","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}
Response sensitivity analysis plays an important role in optimization algorithms that require gradients or sensitivities of structural responses, including finite element reliability analysis, structural optimization, system identification and finite element model updating. The direct differentiation method (DDM) is an accurate and efficient method for response sensitivity calculations. However, it may require significant efforts to differentiate analytically and software implement the finite element response sensitivities at various hierarchies, that is, structure, element and material levels. Among these calculations, the stress sensitivity calculation is often one of the most challenging, particularly for complicated three‐dimensional or nonsmooth material constitutive models. To overcome this challenge, this paper presents a DDM formulation that bypasses the analytical stress differentiation step, typically the most complicated part of the DDM, by introducing a perturbed stress sensitivity (PSS) approach within the DDM framework (referred to as DDM‐PSS). Both conditional and unconditional stress sensitivities are calculated with different perturbation strategies, resulting in negligible computational effort. The method is applicable to any material model and retains accuracy comparable to that of the traditional DDM, while eliminating the need for model‐specific analytical stress sensitivity derivations. Three examples are presented to validate the proposed method, including a large complex nonlinear dam‐reservoir‐foundation coupling system. A detailed study of accuracy and efficiency is provided. The results demonstrate that DDM‐PSS offers an accurate solution for response sensitivity analysis with minimal effort and almost identical computation time to that of traditional DDM.
{"title":"Seismic Response Sensitivity Analysis of Large Complex Nonlinear Systems Using a Direct Differentiation Method With Perturbed Stress Sensitivity","authors":"Quan Gu, Zhe Lin, Lei Wang","doi":"10.1002/nag.70250","DOIUrl":"https://doi.org/10.1002/nag.70250","url":null,"abstract":"Response sensitivity analysis plays an important role in optimization algorithms that require gradients or sensitivities of structural responses, including finite element reliability analysis, structural optimization, system identification and finite element model updating. The direct differentiation method (DDM) is an accurate and efficient method for response sensitivity calculations. However, it may require significant efforts to differentiate analytically and software implement the finite element response sensitivities at various hierarchies, that is, structure, element and material levels. Among these calculations, the stress sensitivity calculation is often one of the most challenging, particularly for complicated three‐dimensional or nonsmooth material constitutive models. To overcome this challenge, this paper presents a DDM formulation that bypasses the analytical stress differentiation step, typically the most complicated part of the DDM, by introducing a perturbed stress sensitivity (PSS) approach within the DDM framework (referred to as DDM‐PSS). Both conditional and unconditional stress sensitivities are calculated with different perturbation strategies, resulting in negligible computational effort. The method is applicable to any material model and retains accuracy comparable to that of the traditional DDM, while eliminating the need for model‐specific analytical stress sensitivity derivations. Three examples are presented to validate the proposed method, including a large complex nonlinear dam‐reservoir‐foundation coupling system. A detailed study of accuracy and efficiency is provided. The results demonstrate that DDM‐PSS offers an accurate solution for response sensitivity analysis with minimal effort and almost identical computation time to that of traditional DDM.","PeriodicalId":13786,"journal":{"name":"International Journal for Numerical and Analytical Methods in Geomechanics","volume":"30 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2026-02-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146122029","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}
Jinwei Fu, Hadi Haeri, Vahab Sarfarazi, Mohammad Ijani, Mohammad Fatehi Marji
This article explores the micromechanical failure processes and acoustic emission (AE) characteristics of rock‐like specimens containing pre‐formed holes under spherical loading, both in confined and unconfined conditions. Gypsum, which serves as a granular rock‐like medium, was used to prepare specimens with two holes, in which stainless steel balls were placed. A uniaxial compression machine applied the loading, while complementary particle‐based numerical simulations were conducted using particle flow code (PFC2D) to analyze crack initiation, propagation, and coalescence at the particle level. This study investigates nine‐hole configurations (three‐hole diameters × three‐hole spacings) under unconfined conditions, in addition to several configurations under confined conditions. Two‐hole configurations were examined to assess the impact of hole spacing on fracture evolution and AE activity. Under unconfined loading, tensile cracks initiated at the boundaries of the holes and propagated inward, leading to the coalescence of adjacent holes, as well as outward until they reached the boundary of the specimen. This process was accompanied by a stress drop on the stress–displacement curve, reflecting the failure of the granular bridges between holes. The magnitude of this stress drop decreased as the spacing between the holes increased. In the case of confined loading, similar tensile crack initiation was observed, but diagonal and shear fractures became more prominent, particularly around the loading boundaries. Increased wall displacements led to more branching and heightened shear activity. Both experimental and particle‐based numerical analyses provide new insights into granular fracture mechanisms, hole interactions, and the AE response in bonded granular systems under different loading conditions.
{"title":"Micromechanical Fracture and Acoustic Emission (AE) Characteristics of Bonded Granular Materials With Holes Under Confined and Unconfined Loading: An Experimental Study and Particle Flow Code (PFC) Analysis","authors":"Jinwei Fu, Hadi Haeri, Vahab Sarfarazi, Mohammad Ijani, Mohammad Fatehi Marji","doi":"10.1002/nag.70257","DOIUrl":"https://doi.org/10.1002/nag.70257","url":null,"abstract":"This article explores the micromechanical failure processes and acoustic emission (AE) characteristics of rock‐like specimens containing pre‐formed holes under spherical loading, both in confined and unconfined conditions. Gypsum, which serves as a granular rock‐like medium, was used to prepare specimens with two holes, in which stainless steel balls were placed. A uniaxial compression machine applied the loading, while complementary particle‐based numerical simulations were conducted using particle flow code (PFC2D) to analyze crack initiation, propagation, and coalescence at the particle level. This study investigates nine‐hole configurations (three‐hole diameters × three‐hole spacings) under unconfined conditions, in addition to several configurations under confined conditions. Two‐hole configurations were examined to assess the impact of hole spacing on fracture evolution and AE activity. Under unconfined loading, tensile cracks initiated at the boundaries of the holes and propagated inward, leading to the coalescence of adjacent holes, as well as outward until they reached the boundary of the specimen. This process was accompanied by a stress drop on the stress–displacement curve, reflecting the failure of the granular bridges between holes. The magnitude of this stress drop decreased as the spacing between the holes increased. In the case of confined loading, similar tensile crack initiation was observed, but diagonal and shear fractures became more prominent, particularly around the loading boundaries. Increased wall displacements led to more branching and heightened shear activity. Both experimental and particle‐based numerical analyses provide new insights into granular fracture mechanisms, hole interactions, and the AE response in bonded granular systems under different loading conditions.","PeriodicalId":13786,"journal":{"name":"International Journal for Numerical and Analytical Methods in Geomechanics","volume":"31 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2026-02-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146122030","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}
Lun Hua, Yue Gui, Yi Tian, Jinxiao Luo, Wenbing Wu, Mingxi Ou
This paper presents a semi‐analytical investigation into the thermal consolidation behavior of saturated normally‐consolidated (NC) clay within a two‐dimensional semi‐infinite domain, incorporating both thermal contraction and a realistic impeded boundary condition. A novel thermo‐hydro‐mechanical (THM) coupling model is established, building upon a constitutive relationship that decomposes thermal strain into three components to accurately capture the irreversible volumetric contraction of saturated NC clay under drained heating. The corresponding semi‐analytical solutions for the temperature, excess pore water pressure (EPWP), and displacement under a strip‐type thermomechanical load are derived using Laplace‐Fourier transformation and validated against existing analytical results. Parametric studies reveal that heating induces complex EPWP distributions, including transient negative pore pressure zones. Soil deformation exhibits an initial heave followed by consolidation settlement, the magnitude of which is primarily controlled by the ultimate temperature increase. The surface drainage condition significantly influences the response, with poorly permeable boundaries promoting heave‐dominant deformation. Furthermore, both the magnitude and spatial extent of the thermal load are shown to be critical factors governing the evolution of EPWP and the rate of heat transfer.
{"title":"Semi‐Analytical Study on Thermal Consolidation of Semi‐Infinite Saturated Normally‐Consolidated Soils Under Impeded Boundary","authors":"Lun Hua, Yue Gui, Yi Tian, Jinxiao Luo, Wenbing Wu, Mingxi Ou","doi":"10.1002/nag.70262","DOIUrl":"https://doi.org/10.1002/nag.70262","url":null,"abstract":"This paper presents a semi‐analytical investigation into the thermal consolidation behavior of saturated normally‐consolidated (NC) clay within a two‐dimensional semi‐infinite domain, incorporating both thermal contraction and a realistic impeded boundary condition. A novel thermo‐hydro‐mechanical (THM) coupling model is established, building upon a constitutive relationship that decomposes thermal strain into three components to accurately capture the irreversible volumetric contraction of saturated NC clay under drained heating. The corresponding semi‐analytical solutions for the temperature, excess pore water pressure (EPWP), and displacement under a strip‐type thermomechanical load are derived using Laplace‐Fourier transformation and validated against existing analytical results. Parametric studies reveal that heating induces complex EPWP distributions, including transient negative pore pressure zones. Soil deformation exhibits an initial heave followed by consolidation settlement, the magnitude of which is primarily controlled by the ultimate temperature increase. The surface drainage condition significantly influences the response, with poorly permeable boundaries promoting heave‐dominant deformation. Furthermore, both the magnitude and spatial extent of the thermal load are shown to be critical factors governing the evolution of EPWP and the rate of heat transfer.","PeriodicalId":13786,"journal":{"name":"International Journal for Numerical and Analytical Methods in Geomechanics","volume":"1 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2026-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146122034","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}
Variations in environmental humidity induce changes in the moisture content of rockfill materials, thereby influencing their creep behavior. In core rockfill dams, reservoir impoundment alters the environmental humidity conditions of the upstream rockfill materials, which often induces nonuniform creep deformation between the upstream and downstream zones. Excessive nonuniform creep deformation may lead to structural damage of the dam during its subsequent operation. This study presents an in‐depth analysis of the impact of nonuniform creep deformation following reservoir impoundment on the long‐term safety of an asphalt–concrete core dam exhibiting pre‐existing crest cracks. To this end, a classical empirical creep model was modified to incorporate the humidity‐dependent creep behavior of rockfill materials and subsequently integrated into a finite‐element program for numerical analysis. Model parameters used in the modified creep model were identified using on‐site monitoring data through the backpropagation‐particle swarm optimization inversion method. The good agreement between the calculated results and existing monitoring data indicates the validity of the proposed numerical simulation scheme. Based on the simulation results, a thorough discussion is presented to clarify the causes of crest cracking and evaluate the safety of the dam. Stress analysis of the core crest pavement reveals that differential saturation levels on either side of the core wall induce tensile stresses in the pavement, which lead to cracking. Further stress analysis of the core wall suggests a low probability of cracking or hydraulic fracturing. Meanwhile, predictive deformation analyses indicate that creep deformation is expected to stabilize approximately 4 years after impoundment.
{"title":"Investigation of Nonuniform Creep Behavior and Crest Cracking of an Asphalt–Concrete Core Rockfill Dam After Reservoir Impoundment","authors":"Wen He, Hangyu Mao, Sihong Liu, Liujiang Wang, Chaomin Shen","doi":"10.1002/nag.70251","DOIUrl":"https://doi.org/10.1002/nag.70251","url":null,"abstract":"Variations in environmental humidity induce changes in the moisture content of rockfill materials, thereby influencing their creep behavior. In core rockfill dams, reservoir impoundment alters the environmental humidity conditions of the upstream rockfill materials, which often induces nonuniform creep deformation between the upstream and downstream zones. Excessive nonuniform creep deformation may lead to structural damage of the dam during its subsequent operation. This study presents an in‐depth analysis of the impact of nonuniform creep deformation following reservoir impoundment on the long‐term safety of an asphalt–concrete core dam exhibiting pre‐existing crest cracks. To this end, a classical empirical creep model was modified to incorporate the humidity‐dependent creep behavior of rockfill materials and subsequently integrated into a finite‐element program for numerical analysis. Model parameters used in the modified creep model were identified using on‐site monitoring data through the backpropagation‐particle swarm optimization inversion method. The good agreement between the calculated results and existing monitoring data indicates the validity of the proposed numerical simulation scheme. Based on the simulation results, a thorough discussion is presented to clarify the causes of crest cracking and evaluate the safety of the dam. Stress analysis of the core crest pavement reveals that differential saturation levels on either side of the core wall induce tensile stresses in the pavement, which lead to cracking. Further stress analysis of the core wall suggests a low probability of cracking or hydraulic fracturing. Meanwhile, predictive deformation analyses indicate that creep deformation is expected to stabilize approximately 4 years after impoundment.","PeriodicalId":13786,"journal":{"name":"International Journal for Numerical and Analytical Methods in Geomechanics","volume":"173 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2026-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146122036","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}
To solve limestone floor water inrush and reduce accidents, this paper studies Fengxianglin Coal Mine. It uses field investigation, mechanical experiments, similar simulation and engineering numerical simulation to explore limestone floor damage, Maokou Formation fracture development, and the influence of advancing distance, coal seam burial depth, aquitard thickness and floor water pressure on floor water inrush during coal—seam mining above confined water. Results show that stress—strain curves of limestone with different water content have four stages: initial stress growth, crack compaction, stress increase and stress drop. Water dissolution softens limestone, enhances nonlinear deformation and changes failure mode from local brittle to overall plastic. The coupling of pore water pressure and mining stress reduces floor strata strength and raises water inrush risk. Digital image correlation (DIC) technology monitoring shows that in the process of working face advancing. The maximum principal strain concentration range and degree of strata gradually expand. The strain distribution is ‘W’ shape, and the displacement curve is irregular ‘M’ shape. Water inrush occurs when the floor damage zone connects with the aquifer water channel. Numerical simulation reveals that increasing advancing distance raises floor fractures and pore pressure. Pore pressure distribution changes from inverted ‘circular arch’ to inverted ‘concave’ with increasing coal seam burial depth. Increasing aquitard thickness reduces pore pressure and inhibits fracture propagation. Increasing floor water pressure accelerates crack propagation and heightens water inrush risk.
{"title":"Study on Water‐Rock Coupling Damage Mechanism and Water Inrush Prevention and Control of Overlying Coal Seam in Karst Confined Aquifer in Karst Area","authors":"Jiabao Liu, Guiyi Wu, Dezhong Kong, Fuxing Mei, Gaofeng Song, Yujun Zuo, Qingzhi Liu","doi":"10.1002/nag.70265","DOIUrl":"https://doi.org/10.1002/nag.70265","url":null,"abstract":"To solve limestone floor water inrush and reduce accidents, this paper studies Fengxianglin Coal Mine. It uses field investigation, mechanical experiments, similar simulation and engineering numerical simulation to explore limestone floor damage, Maokou Formation fracture development, and the influence of advancing distance, coal seam burial depth, aquitard thickness and floor water pressure on floor water inrush during coal—seam mining above confined water. Results show that stress—strain curves of limestone with different water content have four stages: initial stress growth, crack compaction, stress increase and stress drop. Water dissolution softens limestone, enhances nonlinear deformation and changes failure mode from local brittle to overall plastic. The coupling of pore water pressure and mining stress reduces floor strata strength and raises water inrush risk. Digital image correlation (DIC) technology monitoring shows that in the process of working face advancing. The maximum principal strain concentration range and degree of strata gradually expand. The strain distribution is ‘W’ shape, and the displacement curve is irregular ‘M’ shape. Water inrush occurs when the floor damage zone connects with the aquifer water channel. Numerical simulation reveals that increasing advancing distance raises floor fractures and pore pressure. Pore pressure distribution changes from inverted ‘circular arch’ to inverted ‘concave’ with increasing coal seam burial depth. Increasing aquitard thickness reduces pore pressure and inhibits fracture propagation. Increasing floor water pressure accelerates crack propagation and heightens water inrush risk.","PeriodicalId":13786,"journal":{"name":"International Journal for Numerical and Analytical Methods in Geomechanics","volume":"558 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2026-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146122033","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}
Based on uniaxial and triaxial compression tests of coal and sandstone, deformation and strength parameters for the coal‐rock‐bolt composite structure were determined, providing key inputs for subsequent single free‐surface loading simulation. A numerical model characterizing coal‐rock composite anchored body with through‐going joints was developed using FLAC 3D 9.0 integrated with Fish scripting language. By developing a real‐time energy density tracking program, multi‐factor coupled simulation loading experiments were systematically conducted. The simulations reveal the strength parameter degradation and energy evolution law of the anchored bodies of the coal‐rock composite with through‐going joints. Results indicate that the ultimate strength of the coal‐rock combination depends on the coal mass, the plastic deformation capacity relies more on the rock mass, with the overall stiffness exhibiting intermediate characteristics between coal and rock. Both peak strength and energy storage limits demonstrate positive correlations with interfacial roughness. Furthermore, for the composite geological bodies formed by coal and rock, anchoring reinforcement applied to weaker zones effectively coordinates stress and energy distribution within the composite structure, suppressing localized damage propagation, thereby increasing the energy storage threshold and delaying the catastrophic failure time of the anchored body. Therefore, a “weakness‐compensation‐first” support strategy is proposed to enhance the overall geomechanical performance of the composite structure.
基于煤和砂岩的单轴和三轴压缩试验，确定了煤-岩-锚杆复合结构的变形和强度参数，为后续的单自由面加载模拟提供了关键输入。利用FLAC 3D 9.0集成了Fish脚本语言，建立了煤岩复合贯通节理锚固体的数值模型。通过开发实时能量密度跟踪程序，系统地进行了多因素耦合模拟加载实验。模拟结果揭示了贯通节理煤岩复合材料锚固体的强度参数退化和能量演化规律。结果表明：煤岩组合的极限强度取决于煤体，塑性变形能力更多地取决于岩体，整体刚度表现出介于煤岩之间的中间特征；峰值强度和能量存储极限均与界面粗糙度呈正相关。此外，对于煤岩复合地质体，在较弱区域进行锚固加固可以有效协调复合结构内部的应力和能量分布，抑制局部损伤传播，从而提高储能阈值，延缓锚体的突变破坏时间。因此，提出了“弱点-补偿-优先”的支护策略，以提高复合材料结构的整体地质力学性能。
{"title":"Fracture Mechanism and Energy Dissipation Characteristics of Coal‐Rock Composite Anchored Body With Through‐Going Joints","authors":"Xue‐kui Xin, Qing‐bin Meng, Xiang‐hui Zhang","doi":"10.1002/nag.70264","DOIUrl":"https://doi.org/10.1002/nag.70264","url":null,"abstract":"Based on uniaxial and triaxial compression tests of coal and sandstone, deformation and strength parameters for the coal‐rock‐bolt composite structure were determined, providing key inputs for subsequent single free‐surface loading simulation. A numerical model characterizing coal‐rock composite anchored body with through‐going joints was developed using FLAC <jats:sup>3D</jats:sup> 9.0 integrated with Fish scripting language. By developing a real‐time energy density tracking program, multi‐factor coupled simulation loading experiments were systematically conducted. The simulations reveal the strength parameter degradation and energy evolution law of the anchored bodies of the coal‐rock composite with through‐going joints. Results indicate that the ultimate strength of the coal‐rock combination depends on the coal mass, the plastic deformation capacity relies more on the rock mass, with the overall stiffness exhibiting intermediate characteristics between coal and rock. Both peak strength and energy storage limits demonstrate positive correlations with interfacial roughness. Furthermore, for the composite geological bodies formed by coal and rock, anchoring reinforcement applied to weaker zones effectively coordinates stress and energy distribution within the composite structure, suppressing localized damage propagation, thereby increasing the energy storage threshold and delaying the catastrophic failure time of the anchored body. Therefore, a “weakness‐compensation‐first” support strategy is proposed to enhance the overall geomechanical performance of the composite structure.","PeriodicalId":13786,"journal":{"name":"International Journal for Numerical and Analytical Methods in Geomechanics","volume":"56 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2026-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146122035","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}
The artificial ground freezing (AGF) method is frequently affected by groundwater seepage. Due to the combined effects of convective heat transfer by water flow and conductive heat transfer from the cold source, the artificial freezing curtain in a seepage field exhibits significant asymmetry. Most existing studies focus on brine freezing, whereas the ultra‐low temperature properties of liquid nitrogen make it suitable for freezing projects in high‐seepage environments. This study investigates the temperature field of three‐pipe liquid nitrogen freezing. An equivalent partitioning and segmentation method is employed to determine the shape of the freezing curtain, an analytical solution for the steady‐state temperature field of a three‐pipe liquid nitrogen freezing curtain under high seepage‐flow is derived. Through model tests and numerical simulations, the evolution of the three‐pipe liquid nitrogen freezing temperature field under varying seepage conditions is analyzed, and the validity of the formula is verified. The results indicate that the calculated freezing temperature aligns well with both experimental and numerical results, confirming the validity of the analytical solution through model testing. A high‐flow environment enhances heat transfer efficiency at the solid surface. As the flow rate increases, heat transfer efficiency improves, and the asymmetry of the freezing curtain becomes more pronounced. In multi‐pipe freezing, the “adjacent pipe effect” occurs. When adjacent freezing fronts contract to the critical threshold ( L c ), the freezing front expands more rapidly, shortening the intersection time of the freezing curtain. These findings provide valuable insights for designing liquid nitrogen artificial freezing systems in high seepage‐flow.
{"title":"Analytical Solution for the Steady‐State Temperature Field of Three‐Pipe Liquid Nitrogen Freezing Under High Seepage‐Flow Conditions","authors":"Zhe Yang, Haibing Cai, Bin Wang, Changqiang Pang","doi":"10.1002/nag.70254","DOIUrl":"https://doi.org/10.1002/nag.70254","url":null,"abstract":"The artificial ground freezing (AGF) method is frequently affected by groundwater seepage. Due to the combined effects of convective heat transfer by water flow and conductive heat transfer from the cold source, the artificial freezing curtain in a seepage field exhibits significant asymmetry. Most existing studies focus on brine freezing, whereas the ultra‐low temperature properties of liquid nitrogen make it suitable for freezing projects in high‐seepage environments. This study investigates the temperature field of three‐pipe liquid nitrogen freezing. An equivalent partitioning and segmentation method is employed to determine the shape of the freezing curtain, an analytical solution for the steady‐state temperature field of a three‐pipe liquid nitrogen freezing curtain under high seepage‐flow is derived. Through model tests and numerical simulations, the evolution of the three‐pipe liquid nitrogen freezing temperature field under varying seepage conditions is analyzed, and the validity of the formula is verified. The results indicate that the calculated freezing temperature aligns well with both experimental and numerical results, confirming the validity of the analytical solution through model testing. A high‐flow environment enhances heat transfer efficiency at the solid surface. As the flow rate increases, heat transfer efficiency improves, and the asymmetry of the freezing curtain becomes more pronounced. In multi‐pipe freezing, the “adjacent pipe effect” occurs. When adjacent freezing fronts contract to the critical threshold ( <jats:italic> L <jats:sub>c</jats:sub> </jats:italic> ), the freezing front expands more rapidly, shortening the intersection time of the freezing curtain. These findings provide valuable insights for designing liquid nitrogen artificial freezing systems in high seepage‐flow.","PeriodicalId":13786,"journal":{"name":"International Journal for Numerical and Analytical Methods in Geomechanics","volume":"26 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2026-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146122032","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}
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