为研究承压水上开采时含隐伏断层底板的安全性，根据断裂力学理论建立导水断层活化扩展的理论模型。将煤层底板看做半平面无限体，把底板中含水层顶部以上的隐伏断层建模为有限宽度板条的倾斜边缘裂纹。根据采场底板的支承压力分布规律，将其简化为若干分段线性载荷加载至底板，纳入断层产状、断层在底板中埋深、工作面推进距离、含水层水压、断层面摩擦角等各种参数，推导得到底板内任意一点的应力公式。将其应用到隐伏断层面上各点，综合考虑各点法向应力、剪应力对裂纹活化的影响，计算得到采动条件下断层面上的有效切应力分布。该有效切应力剔除了裂纹面上摩擦效应对压剪裂纹扩展的影响，将其代入断裂力学相关公式，计算得到隐伏断层前缘的应力强度因子，最后通过定义突水安全指数建立了底板突水判据。以某矿带压开采工作面为例，根据相应水文和地质资料，计算得到在工作面推过隐伏断层的整个过程中断层活化突水危险性的变化规律，所得结论与工作面现场微震监测数据相符，即当工作面推进至采空区位于隐伏断层正上方区域时，断层面承受有效剪切最充分，剪切应力强度因子最大，突水安全指数达到峰值，这与现场微震监测结果中显示的在该推进阶段中，原有隐伏断层附近派生裂隙集中出现、突水危险性最高的结果相符合。
For analyzing the security of floor containing insidious fault while mining above water, a fracture mechanical model is established in order to describe the activation and growth of insidious fault. First, from the beginning of aquifer top in floor, the above part of insidious fault is modeled as an oblique edge crack of finite width plate. Second, involving the effects of normal stress and shear stress for fault activation, effective shear stress distribution in the fault plane is calculated in the mining conditions. Third, according to attitude and burial depth in the floor of fault, distance of face advancing, water pressure of the aquifer, and angle of friction in the fault plane, the compress-shearing stress intensity factor of insidious fault is presented. Finally, the safety index is defined for establishing the criterion of water inrush. Taking a certain coal face mining under pressure for example, in accordance with its hydrologic and geological data, variation of risk about water inrush from activating fault is obtained during the whole face advancing across the fault. The conclusion coincides with microseismic monitoring data at the site. This analysis may provide suggestions for safe and rational coal mining and improve numerical or theoretical models of water inrush in floor.
[1] 刘其声. 关于突水系数的讨论[J]. 煤田地质与勘探, 2009, 37(4): 34- 42. Liu Qisheng. A discussion on water inrush coefficient[J]. Coal Geology & Exploration, 2009, 37(4): 34-42.
[2] 刘伟韬, 张文泉, 高延法, 等. 底板突水预测专家系统研究[J]. 山东矿 业学院学报, 1998, 17(4): 333-338. Liu Weitao, Zhang Wenquan, Gao Yanfa, et al. Research on expert system for predicting floor water-irruption[J]. Journal of Shandong Mining Institute, 1998, 17(4): 333-338.
[3] 李娜娜, 施龙青, 李忠建, 等. 基于系统聚类法的底板突水危险性评价[J]. 矿业安全与环保, 2011, 38(2): 28-30. Li Nana, Shi Longqing, Li Zhongjian, et al. Evaluating water inrush from floor based on system clustering method[J]. Mining Safety & Environmental Protection, 2011, 38(2): 28-30.
[4] 武强, 张志龙, 张生元, 等. 煤层底板突水评价的新型实用方法II—脆 弱性指数法[J]. 煤炭学报, 2007, 32(11): 1121-1126. Wu Qiang, Zhang Zhilong, Zhang Shengyuan, et al. A new practical methodology of the coal floor water bursting evaluating II: The vulnerable index method[J]. Journal of China Coal Society, 2007, 32 (11): 1121-1126.
[5] 施龙青, 曲有刚, 徐望国. 采场底板断层突水判别方法[J]. 矿山压力与 顶板管理, 2000(2): 49-52. Shi Longqing, Qu Yougang, Xu Wangguo. Discriminant method of water inrush from mining floor[J]. Ground Pressure and Strata Control, 2000(2): 49-52.
[6] 杨善安. 采场底板断层突水及其防治方法[J]. 煤炭学报, 1994, 19(6): 620-625. Yang Shan'an. Prevention and control of water inrush from faults in floor rocks in the workings[J]. Journal of China Coal Society, 1994, 19(6): 620-625.
[7] 钱鸣高, 缪协兴, 许家林, 等. 岩层控制的关键层理论[M]. 徐州: 中国 矿业大学出版社, 2003. Qian Minggao, Miao Xiexing, Xu Jialin, et al. Key strata theory in ground control[M]. Xuzhou: China University of Mining and Technology Press, 2003.
[8] 陈忠辉, 胡正平, 李辉, 等. 煤矿隐伏断层突水的断裂力学模型及力学 判据[J]. 中国矿业大学学报, 2011, 40(5): 673-677. Chen Zhonghui, Hu Zhengping, Li Hui, et al. Fracture mechanical model and criteria of insidious fault water inrush in coal mines[J]. Journal of China University of Mining & Technology, 2011, 40(5): 673- 677.
[9] 钱鸣高, 石平五. 矿山压力与岩层控制[M]. 徐州: 中国矿业大学出版 社, 2003. Qian Minggao, Shi Pingwu. Mining pressure and strata control[M]. Xuzhou: China University of Mining and Technology Press, 2003.
[10] 冯西桥, 余寿文. 准脆性材料细观损伤力学[M]. 北京: 高等教育出版 社, 2002. Feng Xiqiao, Yu Shouwen. Damage micromechanics of quasi- brittle materials[M]. Beijing: Higher Education Press, 2002.
[11] 中国航空研究院. 应力强度因子手册[M]. 北京: 科学出版社, 1993. Chinese Aeronautical Establishment. Manual of stress intensity factor[M]. Beijing: Science Press, 1993.
[12] 陈勉, 金衍, 袁长友. 围压条件下岩石断裂韧性的实验研究[J]. 力学 与实践, 2001, 23(4): 32-35. Chen Mian, Jin Yan, Yuan Changyou. Study on the experiment for fracture toughness under confining pressure[J]. Mechanics in Engineering, 2001, 23(4): 32-35.
