开采沉陷对矿区地表裂缝的采动累积效应分析

Analysis on mining-induced cumulative effective of surface cracks in mining areas

基于开采沉陷学和岩石力学理论分析矿区地表裂缝的采动累积效应。采用概率积分法、胡克定律和莫尔-库伦破坏准则等方法描述并量化地表拉伸裂缝的采动累积效应表征指标,提出了采动裂缝时间拥挤效应和采动延迟效应表征指标及采动空间拥挤效应表征指标。对研究区地表裂缝采动时间拥挤效应的实地观测与数值模拟分析结果表明,上下分层动态裂缝持续时间和永久裂缝显现时刻与地表移动活跃期吻合;采动空间拥挤效应分析结果表明,采动裂缝水平延伸长度、宽度和深度均比永久裂缝小,下分层开采裂缝比上分层发育,下山方向比其他部位裂缝发育。

The paper analyzes the mining-induced cumulative effective of surface cracks based on Mining subsidence science and rock mechanics theory. The cumulative effective characterization indexes of tension cracks were described and quantized by means of probability integral method, the hooker law and Moore-the coulomb failure cri- teria. The dynamic crackg duration and the permanent crack~ appearance time was proposed as the evaluating indi- cators of the time crowded effective and the delay effective. The density, the length of horizontal extension, the width, the depth of cracks and the falls of step cracks was proposed as the evaluating indicators of the space crowd- ed effective. Case field observation and the numerical simulation results of the time crowded effective show that the dynamic crack＇s duration and the permanent crack＇s appearance time accords with the activity period of surface movement. The space crowded effective analysis shows that the horizontal length, the width, the depth of dynamic cracks is smaller than the permanent ones. Mining cracks of lower slice more develop than cracks of upper slice. Cracks at the descends mountain direction more develop than else directions