(1. School of Energy and Mining Engineering, China University of Mining and Technology (Beijing), Beijing 100083, China;
2. Joint National-Local Engineering Research Centre for Safe and Precise Coal Mining, Anhui University of Science and Technology, Huainan, Anhui 232001, China; 3. Engineering Research Center of Green and Intelligent Mining for Thick Coal Seam, Ministry of Education, China University of Mining and Technology (Beijing), Beijing 100083, China)
Abstract：The stress-pore-seepage coupling mechanism in sandstone aquifers affected by mining disturbances is crucial for safeguarding roof aquifers and predicting contaminant transport during coordinated coal and uranium mining operations. This study employs nano-CT scanning, nuclear magnetic resonance (NMR) data calibration, and three-dimensional model reconstruction to perform fluid-solid coupling numerical simulations at the microscale within sandstone. Based on pore size distribution, the NMR T2 spectrum can be broadly categorized into four segments: pores smaller than 1 nm, pores between 1 nm and 1 ?m, pores between 1 ?m and 6 ?m, and pores larger than 6 ?m. The NMR T2 spectrum exhibits two peaks at pore sizes of 1 nm–1 ?m and above 6 ?m. NMR results during seepage indicate that, under an external load of 2 MPa and an increase in water pressure from 0 MPa to 0.5 MPa, nanopore (1 nm to 1 ?m) porosity decreases from 5.06% to 4.65%, while micropore (＞1 ?m) porosity increases from 0.14% to 0.6%. As external stress continues to rise, both nanopore and micropore porosity decrease linearly: nanopores decline from 4.65% to 4.24% (a reduction of approximately 8.82%), and micropores decrease from 0.6% to 0.46% (a reduction of approximately 23.3%). The proportion of total porosity remains largely unchanged, with nanopores accounting for about 90% and micropores comprising approximately 10%. A sandstone pore reconstruction method was developed utilizing NMR and nano-CT data, with a minimum representative element size of 100 pixels. Microscopic simulations reveal that increasing external stress leads to complex stress concentration and attenuation near pores. During seepage, flow lines converge toward pore regions and preferentially traverse zones with lower effective stress. Furthermore, reverse flow and boundary layer effects occur internally during seepage, intensifying under increasing stress.
[1] LI Z，ZHOU Z Q. Numerical simulation of rock fracture and permeability characteristics under stress-seepage-damage coupling action[J]. International Journal of Geomechanics，2023，23(1)：04022257.
[2] HUANG X，JIN J H，SONG C L，et al. Seepage modelling and seepage-stress coupling properties of fractured rock mass based on equivalent circuit principle[J]. Environmental Earth Sciences，2024，83(16)：458.
[3] LI S C，ZHANG N，LI Q，et al. Stability study of fluid-solid coupled dynamic system of seepage in accumulative broken rock[J]. Arabian Journal of Geosciences，2020，13：1–11.
[4] 裴雪皓，刘月田，薛 亮. 油气藏开发诱导变形的等效力模型及其体积边界元解法[J]. 石油勘探与开发，2025，52(2)：431–440.(PEI Xuehao，LIU Yuetian，XUE Liang. Equivalent force model of deformation induced by oil and gas reservoir development and its volume boundary element method solution[J]. Petroleum Exploration and Development，2025，52(2)：431–440.(in Chinese))
[5] 罗 锦，李英明，郭庆彪，等. 关闭矿井地表抬升变形特征及其影响因素[J]. 煤田地质与勘探，2025，53(2)：1–13.(LUO Jin，LI Yingming，GUO Qingbiao，et al. Deformation characteristics and influential factors of the surface uplift of closed mines[J]. Coal Geology and Exploration，2025，53(2)：1–13.(in Chinese))
[6] 张 晨，钱亚俊，张桂荣，等. 基于流固耦合的河道土质岸坡护岸结构优化数值分析[J]. 岩土工程学报，2020，42(增2)：56–60. (ZHANG Chen，QIAN Yajun，ZHANG Guirong，et al. Numerical analysis of optimization of revetment structures of soil bank slopes of inland rivers[J]. Chinese Journal of Geotechnical Engineering，2020，42(Supp.2)：56–60.(in Chinese))
[7] GUYER R A，KIM H A. Theoretical model for fluid-solid coupling in porous materials[J]. Physical Review E，2015，91(4)：042406.
[8] 赵晨希，张子新，王帅峰，等. 裂隙岩体中隧道开挖流固耦合模型及开挖诱发损伤分析[J]. 哈尔滨工业大学学报，2024，56(7)：28–36.(ZHAO Chenxi，ZHANG Zixin，WANG Shuaifeng，et al. Hydro-mechanical coupling model for tunnel excavation in fractured rocks and analysis on excavation-induced damage[J]. Journal of Harbin Institute of Technology，2024，56(7)：28–36.(in Chinese))
[9] 谢 强，陈昱成，傅 翔，等. 非饱和瞬态渗流的DDA流固耦合模型研究[J]. 岩土工程学报，2024，46(2)：299–306.(XIE Qiang，CHEN Yucheng，FU Xiang，et al. Fluid-solid coupling model for discontinuous deformation analysis of unsaturated transient seepage[J]. Chinese Journal of Geotechnical Engineering，2024，46(2)：299–306.(in Chinese))
[10] 马 丹，李 樯，张吉雄，等. 断层破碎带岩体孔隙结构表征与非线性渗流特性[J]. 煤炭学报，2023，48(2)：666–677.(MA Dan，LI Qiang，ZHANG Jixiong，et al. Pore structure characterization and nonlinear seepage characteristics of rock mass in fault fracture zones[J]. Journal of China Coal Society，2023，48(2)：666–677.(in Chinese))
[11] 慎国强，刘浩杰，王振涛，等. 致密储层复杂缝网流固耦合渗流规律及产能模拟[J]. 大庆石油地质与开发，2023，42(4)：157–165. (SHEN Guoqiang，LIU Haojie，WANG Zhentao，et al. Fluid?solid coupling seepage law and productivity simulation of complex fracture networks in tight reservoirs[J]. Petroleum Geology and Oilfield Development in Daqing，2023，42(4)：157–165.(in Chinese))
[12] 何 涛. 基于ALE有限元法的流固耦合强耦合数值模拟[J]. 力学学报，2018，50(2)：395–404.(HE Tao. A partitioned strong coupling algorithm for fluid-structure interaction using arbitrary Lagrangian-Eulerian finite element formulation[J]. Chinese Journal of Theoretical and Applied Mechanics，2018，50(2)：395–404.(in Chinese))
[13] 蔡少斌，杨永飞，刘 杰. 考虑热流固耦合作用的多孔介质孔隙尺度两相流动模拟[J]. 力学学报，2021，53(8)：2 225–2 234.(CAI Shaobin，YANG Yongfei，LIU Jie. Pore-scale simulation of multiphase flow considering thermo-hydro-mechanical coupling effect in porous media[J]. Chinese Journal of Theoretical and Applied Mechanics，2021，53(8)：2 225–2 234.(in Chinese))
[14] 张俊文，范文兵，宋治祥，等. 真三轴不同应力路径下深部砂岩力学特性[J]. 中国矿业大学学报，2021，50(1)：106–114.(ZHANG Junwen，FAN Wenbing，SONG Zhixiang，et al. Mechanical characteristics of deep sandstone under different true triaxial stress paths[J]. Journal of China University of Mining and Technology，2021，50(1)：106–114.(in Chinese))
[15] 夏开文，王 峥，吴帮标，等. 流固耦合作用下深部岩石动态力学响应研究进展[J]. 煤炭学报，2024，49(1)：454–478.(XIA Kaiwen，WANG Zheng，WU Bangbiao，et al. Research progress on dynamic response of deep rocks under coupled hydraulic-mechanical loading[J]. Journal of China Coal Society，2024，49(1)：454–478.(in Chinese))
[16] 王东亮，郝兵元，梁晓敏. 基于流固耦合的单一裂隙浆液扩散规律研究[J]. 采矿与岩层控制工程学报，2021，3(1)：013038.(WANG Dongliang，HAO Bingyuan，LIANG Xiaomin. Slurry diffusion of single fracture based on fluid-solid coupling[J]. Journal of Mining and Strata Control Engineering，2021，3(1)：013038.(in Chinese))
[17] 娄义黎，邬忠虎，王安礼，等. 流固耦合作用下页岩破裂过程的数值模拟[J]. 煤田地质与勘探，2020，48(1)：105–112.(LOU Yili，WU Zhonghu，WANG Anli，et al. Numerical simulation of rupture process of shale under action of fluid-solid coupling[J]. Coal Geology and Exploration，2020，48(1)：105–112.(in Chinese))
[18] 姚强岭，闫鸿远，李学华，等. 煤岩体流固耦合参变系统的构建与应用[J]. 采矿与安全工程学报，2022，39(3)：429–440.(YAO Qiangling，YAN Hongyuan，LI Xuehua，et al. The construction and application of a coupled parameter transfer system for fluid-mechanical model[J]. Journal of Mining and Safety Engineering，2022，39(3)：429–440.(in Chinese))
[19] ZHANG C，WANG X J，HAN P H，et al. Failure analysis of residual coal pillar under the coupling of mining stress and water immersion in the goaf underground water reservoir[J]. Environmental Earth Sciences，2023，82(12)：309.
[20] ZHANG T，TANG M，YUAN L，et al. Dynamic pore-fracture characteristic and evolution influenced by the underground mining considering the in-situ stress[J]. Energy，2024，289：130119.
[21] 杜 锋，王 凯，董香栾，等. 基于 CT 三维重构的煤岩组合体损伤破坏数值模拟研究[J]. 煤炭学报，2021，46(增1)：253–262.(DU Feng，WANG Kai，DONG Xiangluan，et al. Numerical simulation of damage and failure of coal-rock combination based on CT three-dimensional reconstruction[J]. Journal of China Coal Society，2021，46(Supp.1)：253–262.(in Chinese))
[22] 张 村，贾 胜，王永乐，等. 煤样 CT 扫描重构研究进展：原理，方法及应用[J]. 煤炭学报，2024，49(增2)：800–819.(ZHANG Cun，JIA Sheng，WANG Yongle，et al. CT scanning and reconstruction of coal samples：principle，method and application[J]. Journal of China Coal Society，2024，49(Supp.2)：800–819.(in Chinese))
[23] 王 刚，江成浩，刘世民，等. 基于 CT 三维重建煤骨架结构模型的渗流过程动态模拟研究[J]. 煤炭学报，2018，43(5)：1 390–1 399. (WANG Gang，JIANG Chenghao，LIU Shimin，et al. Dynamic simulation of seepage process based on CT 3D reconstruction of coal skeleton structure model[J]. Journal of China Coal Society，2018，43(5)：1 390–1 399.(in Chinese))
[24] 李承峰，刘乐乐，孙建业，等. 基于数字岩心的含水合物石英砂微观渗流有限元分析[J]. 海洋地质前沿，2020，36(9)：68–72.(LI Chengfeng，LIU Lele，SUN Jianye，et al. Finite element analysis of micro-seepage in hydrate-bearing quartz sands based on digital cores[J]. Marine Geology Frontiers，2020，36(9)：68–72.(in Chinese))
[25] 尚锁贵，高科超，高强勇，等. 裂缝发育程度对低孔隙度岩石渗流特性的影响[J]. 科学技术与工程，2023，23(23)：9 809–9 819. (SHANG Suogui，GAO Kechao，GAO Qiangyong，et al. Influence of fracture development on seepage characteristics of low porosity rocks[J]. Science Technology and Engineering，2023，23(23)：9 809–9 819.(in Chinese))
[26] 翟 成，孙 勇，范宜仁，等. 低场核磁共振技术在煤孔隙结构精准表征中的应用与展望[J]. 煤炭学报，2022，47(2)：828–848.(ZHAI Cheng，SUN Yong，FAN Yiren，et al. Application and prospect of low field nuclear magnetic resonance technology in accurate characterization of coal pore structure[J]. Journal of China Coal Society，2022，47(2)：828–848.(in Chinese))
[27] 张 村，方尚鑫，贾 胜，等. 基于 CT 扫描的三维重构煤体加载损伤演化特征及尺寸效应[J]. 矿业科学学报，2024，9(3)：413–425.(ZHANG Cun，FANG Shangxin，JIA Sheng，et al. Damage evolution characteristics of 3D-reconstructed coal during loading and its size effects based on CT scanning[J]. Journal of Mining Science and Technology，2024，9(3)：413–425.(in Chinese))
[28] ZHANG C，JIA S，HUANG X H，et al. Accurate characterization method of pores and various minerals in coal based on CT scanning[J]. Fuel，2024，358：130128.
[29] BI J，ZHENG K，ZHAO Y，et al. Permeability evolution of coal seam roof sandstone under thermal treatment[J]. Rock Mechanics and Rock Engineering，2024，57(2)：1 137–1 151.
[30] 李 静，彭成乐，周汉国，等. 基于显微红外光谱技术的岩石微观渗流特性研究[J]. 岩石力学与工程学报，2017，36(增1)：3 184–3 191.(LI Jing，PENG Chengle，ZHOU Hanguo，et al. Study on microscopic seepage characteristics of rock based on micro infrared spectra technology[J]. Chinese Journal of Rock Mechanics and Engineering，2017，36(Supp.1)：3 184–3 191.(in Chinese))
[31] 王付勇，岳 慧，朱维耀. 考虑纳米束缚效应与孔—缝组合方式的页岩油藏表观渗透率模型[J]. 石油学报，2025，46(4)：779–788.(WANG Fuyong，YUE Hui，ZHU Weiyao. Shale oil reservoir apparent permeability model considering nano-confinement effects and pore-fracture combination patterns[J]. Acta Petrolei Sinica，2025，46(4)：779–788.(in Chinese))
2026, Vol. 45 
