Fracture mechanical criteria and simulation of floors with Y-shaped branches of major faults in coal mines

Authors

LI Ang, School of Civil Engineering and Architecture, Xi’an University of Science and Technology, Xi’an 710054, China; Shaanxi Key Laboratory of Coal Mine Water Hazard Prevention and Control Technology, Xi’an 710077, ChinaFollow
SUN Jingxin, School of Civil Engineering and Architecture, Xi’an University of Science and Technology, Xi’an 710054, China
ZHANG Wenzhong, Shaanxi Key Laboratory of Coal Mine Water Hazard Prevention and Control Technology, Xi’an 710077, China; CCTEG Xi’an Research Institute (Group) Co., Ltd., Xi’an 710077, China
ZHANG Zhuang, School of Civil Engineering and Architecture, Xi’an University of Science and Technology, Xi’an 710054, ChinaFollow
YANG Yuxuan, SCEGC No.3 Construction Engineering Group Company Ltd., Xi’an 710054, China
WANG Weidong, School of Civil Engineering and Architecture, Xi’an University of Science and Technology, Xi’an 710054, China
LYU Wei, School of Civil Engineering and Architecture, Xi’an University of Science and Technology, Xi’an 710054, China
FAN Liuyi, School of Civil Engineering and Architecture, Xi’an University of Science and Technology, Xi’an 710054, China

Abstract

Objective Despite wide distribution, the branches of major faults (also referred to as the fault branches) tend to be overlooked. However, they represent one of the primary causes of water inrush. Methods Under the engineering geological background of the Liuzhuang coal mine in Anhui Province, this study established a fracture mechanical disaster model for fault branches under the impacts of both seepage and stress based on the criteria for compression-shear fracture of rock masses considering the Mohr-Coulomb criterion. Using this model, this study obtained the critical water pressure and the minimum safe distance between the fault branch and the floor's fractured zone in the case of fault branch splitting. It investigated the influence patterns of factors including the fault dip angle, minimum principal stress, length of a major fault, and seepage water pressure on critical water pressure and the minimum safe distance, determining the dominant influencing factors. Furthermore, this study simulated the evolutionary characteristics of the plastic zones and seepage fields of the fault branches under the mining effects and verified the results using in-situ water pressure tests. Results and Conclusions Key findings are as follows: (1) A higher dip angles of the fault branches corresponded to a higher susceptibility to water inrushes, while a higher minimum principal stress suggested a lower probability of the fissure propagation of the fault branches. (2) In the case where the dip angle of the major fault and the angles between the fault branches and the major fault were both 60°, fault channels were entirely activated and connected when the mining face advanced directly above the fault branch, as indicated by the simulation results. After the mining face advanced 10 m away from the fault branches, fissures at the tip of the fault branches were connected to the fractured zone of the mining face’s floor, resulting in water inrushes from the floor. (3) The in-situ water pressure tests verified the correctness of theoretical calculations, proving that fault branches can cause early interconnection between fissures on the floor and faults, leading to water outflow from the mining face. Overall, the findings of this study provide a reference for setting up waterproof coal pillars in coal mines with Y-shaped fault branches on stope floors.

Keywords

water inrush from floor, Y-shaped fault branch, fracture mechanical model, fault-induced water inrush, numerical simulation, in-situ test

DOI

10.12363/issn.1001-1986.23.11.0776

Recommended Citation

LI Ang, SUN Jingxin, ZHANG Wenzhong, et al. (2024) "Fracture mechanical criteria and simulation of floors with Y-shaped branches of major faults in coal mines," Coal Geology & Exploration: Vol. 52: Iss. 9, Article 10.
DOI: 10.12363/issn.1001-1986.23.11.0776
Available at: https://cge.researchcommons.org/journal/vol52/iss9/10

Reference

[1] 宋文成，梁正召，刘伟韬，等. 采场底板破坏特征及稳定性理论分析与试验研究[J]. 岩石力学与工程学报，2019，38(11)：2208−2218.

SONG Wencheng，LIANG Zhengzhao，LIU Weitao，et al. Theoretical analysis and experimental investigation on failure characteristics and stability of stope floors[J]. Chinese Journal of Rock Mechanics and Engineering，2019，38(11)：2208−2218.

[2] 张鹏，朱学军，孙文斌，等. 采动诱发充填断层活化滞后突水机制研究[J]. 煤炭科学技术，2022，50(3)：136−143.

ZHANG Peng，ZHU Xuejun，SUN Wenbin，et al. Study on mechanism of delayed water inrush caused by mining-induced filling fault activation[J]. Coal Science and Technology，2022，50(3)：136−143.

[3] 马凯，杨天鸿，赵永，等. 上行重复采动底板采空区突水及开采稳定性理论分析[J]. 煤炭学报，2023，48(增刊1)：37−46.

MA Kai，YANG Tianhong，ZHAO Yong，et al. Theoretical analysis of water inrush from goaf in floor and mining stability for upward repeated mining[J]. Journal of China Coal Society，2023，48(Sup.1)：37−46.

[4] 孟凡树，王迎超，焦庆磊，等. 断层破碎带突水最小安全厚度的筒仓理论分析[J]. 哈尔滨工业大学学报，2020，52(2)：89−95.

MENG Fanshu，WANG Yingchao，JIAO Qinglei，et al. Analysis of the minimum safe thickness of water inrush in fault fracture zone based on the silo theory[J]. Journal of Harbin Institute of Technology，2020，52(2)：89−95.

[5] 陆银龙，王连国. 含断层煤层底板损伤破坏演化数值模拟及微震监测研究[J]. 采矿与安全工程学报，2013，30(1)：38−44.

LU Yinlong，WANG Lianguo. Modeling and microseismic monitoring of damage and failure evolution of faulty coal seam floor[J]. Journal of Mining & Safety Engineering，2013，30(1)：38−44.

[6] 李昂. 带压开采下底板渗流与应力耦合破坏突水机理及其工程应用[D]. 西安：西安科技大学，2012.

LI Ang. Water inrush mechanism and engineering application of coupling failure of floor seepage and stress under pressure mining[D]. Xi’an：Xi’an University of Science and Technology，2012.

[7] MA Dan，DUAN Hongyu，ZHANG Jixiong，et al. Numerical simulation of water–silt inrush hazard of fault rock：A three-phase flow model[J]. Rock Mechanics and Rock Engineering，2022，55(8)：5163−5182.

[8] WU Jing，WANG Xintong，WU Li，et al. Parametric study of water inrush in a tunnel crossing a fault based on the “three zones” fault structure[J]. KSCE Journal of Civil Engineering，2022，26(8)：3600−3619.

[9] 向鹏，纪洪广，王金安，等. 开采对断层扰动效应的动力学特征及判据[J]. 岩石力学与工程学报，2015，34(增刊1)：2639−2646.

XIANG Peng，JI Hongguang，WANG Jin’an，et al. Dynamics characteristics and criterion of fault disturbance effect caused by exploitation[J]. Chinese Journal of Rock Mechanics and Engineering，2015，34(Sup.1)：2639−2646.

[10] 于秋鸽，张华兴，张玉军，等. 采动影响下断层活化机理及影响因素分析[J]. 煤炭学报，2019，44(增刊1)：18−30.

YU Qiuge，ZHANG Huaxing，ZHANG Yujun，et al. Analysis of fault activation mechanism and influencing factors caused by mining[J]. Journal of China Coal Society，2019，44(Sup.1)：18−30.

[11] SUN Yunjiang，ZUO Jianping，MI Changning，et al. Investigation on fault activation–induced floor water inrush and its pressure relief control in a 1 000-m depth coal mine[J]. Bulletin of Engineering Geology and the Environment，2023，82(6)：222.

[12] 李樯，马丹，张吉雄，等. 断层带破碎岩体采动剪切变形与渗透性演化规律[J]. 煤田地质与勘探，2023，51(8)：150−160.

LI Qiang，MA Dan，ZHANG Jixiong，et al. Mining-induced shear deformation and permeability evolution law of crushed rock mass in fault zone[J]. Coal Geology & Exploration，2023，51(8)：150−160.

[13] 田雨桐，张平松，吴荣新，等. 煤层采动条件下断层活化研究的现状分析及展望[J]. 煤田地质与勘探，2021，49(4)：60−70.

TIAN Yutong，ZHANG Pingsong，WU Rongxin，et al. Research status and prospect of fault activation under coal mining conditions[J]. Coal Geology & Exploration，2021，49(4)：60−70.

[14] 武滨，谢道雷，韩静，等. 基于煤岩层与断层空间关系的防隔水煤岩柱优化计算[J]. 煤田地质与勘探，2022，50(5)：89−94.

WU Bin，XIE Daolei，HAN Jing，et al. Optimization calculation of the width of waterproof coal pillars in fault zones based on spatial relationship between coal strata and fault[J]. Coal Geology & Exploration，2022，50(5)：89−94.

[15] 李昂，牟谦，刘朝阳，等. 渭北煤田多因素影响下底板扰动破坏深度研究[J]. 煤炭工程，2020，52(5)：138−143.

LI Ang，MU Qian，LIU Chaoyang，et al. Fitting analysis and verification of floor disturbance failure depth under the influence of multiple factors in Weibei Coalfield[J]. Coal Engineering，2020，52(5)：138−143.

[16] 李昂，纪丙楠，牟谦，等. 深部煤岩层复合结构底板破坏机制及应用研究[J]. 岩石力学与工程学报，2022，41(3)：559−572.

LI Ang，JI Bingnan，MU Qian，et al. Failure mechanism of composite structure floors of deep coal and rock strata and its application[J]. Chinese Journal of Rock Mechanics and Engineering，2022，41(3)：559−572.

[17] 李浩，白海波，武建军，等. 岩体循环加卸载力学特性对完整底板导水通道演化影响研究[J]. 岩石力学与工程学报，2018，37(增刊1)：3470−3480.

LI Hao，BAI Haibo，WU Jianjun，et al. Study on the influence of mechanical properties of rock mass cyclic loading and unloading on the evolution of the intact floor[J]. Chinese Journal of Rock Mechanics and Engineering，2018，37(Sup.1)：3470−3480.

[18] 马强. 渭北煤田承压水上开采下组煤贯通型断层底板突水机理研究[D]. 西安：西安科技大学，2020.

MA Qiang. Study on water inrush mechanism of lower group coal through fault floor when mining above confined water in Weibei Coalfield[D]. Xi’an：Xi’an University of Science and Technology，2020.

[19] 邓华锋，李建林，刘杰，等. 考虑裂隙水压力的岩体压剪裂纹扩展规律研究[J]. 岩土力学，2011，32(增刊1)：297−302.

DENG Huafeng，LI Jianlin，LIU Jie，et al. Research on propagation of compression shear fracture in rocks considering fissure water pressure[J]. Rock and Soil Mechanics，2011，32(Sup.1)：297−302.

[20] 蒋明镜，张宁，申志福，等. 含裂隙岩体单轴压缩裂纹扩展机制离散元分析[J]. 岩土力学，2015，36(11)：3293−3300.

JIANG Mingjing，ZHANG Ning，SHEN Zhifu，et al. DEM analyses of crack propagation in flawed rock mass under uniaxial compression[J]. Rock and Soil Mechanics，2015，36(11)：3293−3300.

[21] 陈洪凯，张金浩. 运用等效应力法建立压剪型危岩破坏判据的研究[J]. 地下空间与工程学报，2020，16(3)：827−834.

CHEN Hongkai，ZHANG Jinhao. Study on establishing criterion of pressure-shearing type dangerous rock by equivalent stress method[J]. Chinese Journal of Underground Space and Engineering，2020，16(3)：827−834.

[22] 王进尚，姚多喜，黄浩. 煤矿隐伏断层递进导升突水的临界判据及物理模拟研究[J]. 煤炭学报，2018，43(7)：2014−2020.

WANG Jinshang，YAO Duoxi，HUANG Hao. Critical criterion and physical simulation research on progressive ascending water inrush in hidden faults of coal mines[J]. Journal of China Coal Society，2018，43(7)：2014−2020.

[23] LI Ang，MA Qiang，LIAN Yanqing，et al. Numerical simulation and experimental study on floor failure mechanism of typical working face in thick coal seam in Chenghe mining area of Weibei，China[J]. Environmental Earth Sciences，2020，79(5)：118.

[24] 李刚，刘海振，杨庆贺，等. 带压开采煤层底板破坏特征与突水风险分析[J]. 中国安全科学学报，2022，32(5)：68−76.

LI Gang，LIU Haizhen，YANG Qinghe，et al. Analysis on failure characteristics of coal seam floors and water inrush risks in mining under pressure[J]. China Safety Science Journal，2022，32(5)：68−76.

[25] 中华人民共和国水利部. 水利水电工程钻孔压水试验规程[M]. 北京：中国水利水电出版社，2003.

[26] 国家煤矿安全监察局. 煤矿防治水细则[M]. 北京：煤炭工业出版社，2018.

[27] 孙洪超. 采动断层活化应力演化与煤柱留设研究[D]. 徐州：中国矿业大学，2019.

SUN Hongchao. Study on activation stress evolution of mining fault and coal pillar design[D]. Xuzhou：China University of Mining and Technology，2019.