Integrated monitoring technology of water inrush from coal seam floor and its application
【Abstract】Karst water damage in floor is common in North-China-type coalfield. Because of its concealment and emergency, the prevention and control of water is faced with huge challenges, and monitoring and early-warning technology of floor water inrush has become a necessary measure in the process of the safe production in coal mines. The formation and occurrence of floor water disasters have a process of evolution from conception to development and then to occurrence. In this process, the corresponding water inrush symptoms will be released in different stages of the floor fracture and apparent resistivity of the rock layer. Timely, accurate and effective collection of information can give the specific hydrogeological characteristics in the process of water inrush. It laid a foundation for the establishment of water inrush monitoring system. According to the three elements of water inrush, an integrated monitoring system of water inrush from the floor is built in the working face 11916 of the east mine of Gequan Coal Mine by well–ground–borehole microseismic monitoring and apparent resistivity monitoring. Real-time monitoring of water channels and water sources are carried out to provide a scientific basis for the prediction of water inrush from the floor. The monitoring results show that under normal conditions, the depth of floor damage to working face 11916 is 20–25 m. However, when the working face advanced to the middle roadway on September 14, 2019, the superposed pressure of the material haulage roadway and the middle roadway resulted in the increase in the floor failure depth at this location, reaching 30–35 m. Benxi limestone water from the floor entered the material haulage roadway through the water diversion channel, and the water output from the floor of the working face is 2 m3/h. In addition, from the monitoring results of apparent resistivity, we can see the development of a low resistivity anomaly from the bottom to the top. Research shows that the integrated monitoring system of water inrush from the floor, constructed by well–ground–borehole microseismic monitoring and apparent resistivity monitoring, can capture the symptoms of water inrush from the floor. It is of great significance and practical value to predicting serious water disasters.
【Keywords】 water inrush from floor; microseismic monitoring; apparent resistivity monitoring; Gequan Coal Mine;
(Translated by HAN R)
 ZHANG Wenquan, ZHANG Guangpeng, LI Wei, et al. A model of Fisher’s discriminant analysis for evaluating water inrush risk from coal seam floor [J]. Journal of China Coal Society, 2013, 38 (10): 1831–1836 (in Chinese).
 JIN Dewu. New development of water disaster prevention and control technology in China coal mine and consideration on methodology [J]. Coal Science and Technology, 2017, 45 (5): 141–147 (in Chinese).
 PENG Suping, WANG Jin’an. Safe mining on confined water [M]. Beijing: China Coal Industry Publishing House, 2001: 34–35 (in Chinese).
 ZHANG Jincai, ZHANG Yuzhuo, LIU Tianquan. Seepage of rock mass and water inrush from coal seam floor [M]. Beijing: Geological Publishing House, 1997: 48–51 (in Chinese).
 QIAN Minggao, LIAO Xiexing, XU Jialin, et al. Key stratum theory of strata control [M]. Xuzhou: China University of Mining and Technology Press, 2003: 76–80 (in Chinese).
 SHI Longqing, HAN Jin. Mechanism and prediction of floor water inrush [M]. Xuzhou: China University of Mining and Technology Press, 2004: 45–50 (in Chinese).
 YUAN Fuzhen, MA Ke, ZHUANG Duanyang, et al. Preparation mechanism of water inrush channels in bottom floor of Dongjiahe coal mine based on microseismic monitoring [J]. Journal of China Coal Society, 2019, 44 (6): 1846–1856 (in Chinese).
 WU Qiang. Progress, problems and prospects of prevention and control technology of mine water and reutilization in China [J]. Journal of China Coal Society, 2014, 39 (5): 795–805 (in Chinese).
 YANG Tianhong, SHI Wenhao, LI Shuncai, et al. State of the art and trends of water-inrush mechanism of nonlinear flow in fractured rock mass [J]. Journal of China Coal Society, 2016, 41 (7): 1598–1609 (in Chinese).
 HU Weiyue, ZHAO Chunhu. Trilinear chart classification method of mine water hazard type based on factors of water recharge [J]. Coal Geology&Exploration, 2019, 47 (5): 1–8 (in Chinese).
 LIU Shengdong, LIU Jing, QI Jun, et al. Applied technologies and new advances of parallel electrical method in mining geophysics [J]. Journal of China Coal Society, 2019, 44 (8): 2336–2345.
 LU Jingjin. 3D electrical resistivity inversion and imaging technology for coal mine water-containing/water-conductive structures [J]. Journal of China Coal Society, 2016, 41 (3): 687–695 (in Chinese).
 LIU Demin, YIN Shangxian, LIAN Huiqing, et al. Study on quantitative warning criteria and early warning system for water inrush from coal floor [J]. Coal Engineering, 2019, 51 (4): 16–20 (in Chinese).
 YANG Tianhong, TANG Chun’an, TAN Zhihong, et al. State of the art of inrush models in rock mass failure and developing trend for prediction and forecast of groundwater inrush [J]. Chinese Journal of Rock Mechanics and Engineering, 2007, 26 (2): 268–277 (in Chinese).
 LU Jingjin, WANG Bingchun, YAN Yu. Advances of mine electrical resistivity method applied in coal seam mining destruction and water inrush monitoring [J]. Coal Science and Technology, 2019, 47 (3): 18–26 (in Chinese).
 CHENG Jianyuan, JIN Dan, QIN Si. Challenges faced by geophysical detection technology in mine geological guarantee system [J]. Coal Science and Technology, 2013, 41 (9): 112–116 (in Chinese).
 LIU Chao, WU Shunchuan, CHENG Aiping, et al. Microseis micmonitoring and numerical simulation of the formation of water inrush pathway caused by coal mining [J]. Journal of University of Science and Technology Beijing, 2014, 36 (9): 1129–1135 (in Chinese).
 XU Zhimin, SUN Yajun, GONG Siyuan, et al. Monitoring and numerical simulation of formation of water inrush pathwaycaused by coal mining above confined water with high pressure [J]. Chinese Journal of Rock Mechanics and Engineering, 2012, 31 (8): 1698–1704 (in Chinese).
 ZHANG Pingsong, ZHAI Enfa, CHENG Aimin, et al. Optical fiber monitoring study on characteristics of deformation in floor of deep and thick coal seam during mining [J]. Chinese Journal of Underground Space and Engineering, 2019, 15 (4): 1197–1211 (in Chinese).
 LI Baiyin, SHEN Guanghan, JING Zigang, et al. Theory and practice of preventing water inrush from the floor of mining face [J]. Safety in Coal Mines, 1988 (5): 47–48 (in Chinese).
 SHEN Guanghan, LI Baiying, WU Ge. Theory and practice of special mining [M]. Beijing: China Coal Industry Publishing House, 1992: 56–72 (in Chinese).
 LI Baiying. “Down Three Zones”in the prediction of the water inrush from coalbed floor aquifer-theory, development and application [J]. Journal of Shandong Institute of Mining and Technology (Natural Science), 1999, 18 (4): 11–18v.
 WANG Jingming. In-situ measurement and physical analogue on water inrush from coal floor induced by progressive intrusion of artesian water into protective aquiclude [J]. Chinese Journal of Geotechnical Engineering, 1999, 21 (5): 546–549 (in Chinese).
 WANG Jingming. Physical investigation on water inrush from coal floor induced by pressure water progressive intrusion up into protective aquiclude [J]. Coal Geology&Exploration, 1999, 27 (6): 40–43 (in Chinese).
 WANG Jingming. Water inrush mechanism and application of confined water advancing along coal seam floor[D]. Beijing: China Coal Research Institute, 2004: 78–82 (in Chinese).
 LI Nan, WANG Enyuan, GE Maochen. Microseismic monitoring technique and its applications at coal mines present status and future prospects [J]. Journal of China Coal Society, 2017, 42 (Sup. 1): 83–96 (in Chinese).
 CHEN Ge, SUN Yajun, XU Zhimin, et al. Study progress for microseism monitoring technique on the predication and control in mine water disaster [J]. Metal Mine, 2019 (1): 7–15 (in Chinese).
 JIANG Fuxing, YE Genxi, WANG Cunwen, et al. Application of high-precision microseismic monitoring technique to water inrush monitoring in coal mine [J]. Chinese Journal of Rock Mechanics and Engineering, 2008, 27 (9): 1932–1938 (in Chinese).
 CHENG Guanwen, WANG Yue, MA Tianhui, et al. Research on the partitioning method of the overburden in coal mine based on microseismic monitoring [J]. Chinese Journal of Rock Mechanics and Engineering, 2017, 36 (Sup. 2): 4036–4046 (in Chinese).
 GAO Yuan, ZHOU Huilan, ZHENG Sihua, et al. Preliminary discussion on implication of determination on source depth of earthquake [J]. Earthquake Research in China, 1997, 13 (4), 321–329 (in Chinese).
 MENDECKI A J. Seismic monitoring in mines [M]. London: Chapman and Hall Press, 1997: 67–80.
 TIAN Yue, CHEN Xiaofei. Review of seismic location study [J]. Progress in Geophysics, 2002, 17 (1): 147–155 (in Chinese).
 DUAN Jianhua, YAN Wenchao, NAN Hanchen, et al. Application of mine-hole joint microseismic technology in monitoring the failure depth of working face floor [J]. Coal Geology&Exploration, 2020, 48 (1): 208–213 (in Chinese).
 BRACEW F, ORANGE A S. Electrical resistivity changes in saturated rocks during fracture and frictional sliding [J]. Journal of Geophysical Research, 1968, 73 (4): 1433–1445.
 HOU Kechang. The application of deformation-resistivitymethod to upilift height of the bottom water about the coalseam [J]. Coal Geology&Exploration, 1991, 19 (6): 46–49 (in Chinese).
 LIU Shengdong, WU Rongxin, HU Shuigen, et al. Network distributed parallel electrical exploration system [C]. Proceedings of the annual geophysical conference of China, 2006: 251 (in Chinese).
 LI Jianlou, LIU Shengdong, ZHANG Pingsong, et al. Failure dynamic observation of upper covered stratum under mine using parallel network electricity method [J]. Coal Geology & Exploration, 2008, 36 (2): 61–64 (in Chinese).
 LI S, LIU B, NIE L, et al. Detecting and monitoring of water inrush in tunnels and coal mines using direct current resistivity method: A review [J]. Journal of Rock Mechanics and Geotechnical Engineering, 2015, 7 (4): 469–478.
 LU Jingjin, LI Deshan, WANG Bingchun. Feasibility test of roof resistivity monitoring for super-high mining face [J]. Coal Geology&Exploration, 2019, 47 (Sup. 3): 186–194 (in Chinese).
 HU Weiyue, YIN Shangxian. Dynamic mechanism of water inrush from floor of mining face [J]. Chinese Journal of Rock Mechanics and Engineering, 2010, 29 (Sup. 1): 3344–3349 (in Chinese).