(1. Key Laboratory of Deep Coal Resource Mining，Ministry of Education，School of Mines，China University of Mining and Technology，Xuzhou，Jiangsu 221116，China；2. Key Laboratory of Three Gorges Reservoir Regions Eco-Environment，Ministry of Education，Chongqing University，Chongqing 400045，China；3. School of Earth Sciences and Engineering，Nanjing University，Nanjing，Jiangsu 210023，China)
Abstract：Underground water has repeated intrusion on waterproof coal pillars and on underground reservoir boundaries. Therefore，researching the damaging effect of water intrusion times on crack propagation in coal gives meaningful advice to cope with problems，such as setting the width of water proof coal pillars and storing underground water in arid region of the West China. In this paper，coal samples were wetted by self-made humidifier and then were grouped into dry coal samples，coal samples under once water intrusion，twice water intrusion，third water intrusion and forth water intrusion. By acoustic emission testing，this research found the peak stress and elastic modulus decreased with the growth of water intrusion times but peak strain increased because of the rising water intrusion times. The stiffness-stress curve and accumulative AE counts combined with overall strain-stress curve could evaluate all phases of crack propagation. With the growing times of water intrusion，the stress thresholds of crack closure，crack initiation and crack damage declined linearly. Nevertheless，the percentage of three stress thresholds over peak stress did not vary with the change of water-intrusion times，with 15.52%，31.04% and 67.81% respectively. The experimental results can partly help set the width of waterproof coal pillars and of underground reservoir boundaries.
陈 田1，姚强岭1，杜 茂2，朱晨光3，张 博1. 浸水次数对煤样裂隙发育损伤的实验研究[J]. 岩石力学与工程学报, 2016, 35(S2): 3756-3762.
CHEN Tian1，YAO Qiangling1，DU Mao2，ZHU Chenguang3，ZHANG Bo1. Experimental research of effect of water intrusion times on crack propagation in coal. , 2016, 35(S2): 3756-3762.
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2016, Vol. 35 
