1. Work Safety Key Lab on Prevention and Control of Gas and Roof Disasters for Southern Coal Mines,Hunan University of Science and Technology,Xiangtan　 411201,China;2. Hunan Provincial Key Laboratory of Safe Mining Techniques of Coal Mines,Hunan University of Science and Technology,Xiangtan　411201,China;3. School of Mines,China University of Mining and Technology,Xuzhou　 221116,China;4. School of Resource,Environment and Safety Engi-neering,Hunan University of Science and Technology,Xiangtan　 411201,China

为分析覆岩-煤柱群回收前的稳定性,采用数值模拟软件Flac3D分析了煤柱蠕变期间塑性区发育及内部应力分布形式的演化特征,发现:蠕变过程分为快速变形、缓慢变形及加速失稳3个阶段,并总结出了不同阶段塑性区发育和内部应力分布形式的对应关系;在分析覆岩和煤柱相互作用的基础上,建立了弹性地基薄板模型,推导出了顶板变形、煤柱受力与煤柱塑性区发育范围之间的计算方程组,揭示了覆岩-煤柱群减弱至失稳的动态变化特征;给出了覆岩-煤柱群体系失稳临界时间节点判据和方法,并结合工程算例进行了分析。

Stress and displacement field of roof and standing pillars ( RSP) are always in a state of flux,its stability should be studied before recovering the standing pillars. The creep process of coal pillars is analyzed by Flac3D . The process could be divided into three stages:rapid deformation,slow deformation and accelerating failure. Also,the laws of plastic zone and inner stress distribution pattern of coal pillars at different stages are obtained. Based on the theoreti- cal analysis,one thin plate on elastic found model is established to analyze the relationship between the roof deforma- tion,the force on the pillars and the ranges of plastic zones of coal pillars,and the proposed model allows to reveal the dynamic evolution of the decreasing-failure process of RSP. Furthermore,a criterion for evaluating the critical failure time of RSP is then given in this study,which is illustrated through an engineering case.

国家重点基础研究发展计划(973)资助项目(2013CB227905)；国家自然科学基金创新研究群体资助项目(51421003)；

An Baifu,Qi Wenyue,Lan Lixin,et al. Critical failure time of roof and standing pillars in China western mining area[J]. Journal of China Coal Society,2017,42(2):397-403.