不等长工作面台阶区域覆岩运动诱冲机制及防治

针对阳城煤矿不等长工作面台阶区域发生冲击地压灾害问题，基于工作面特殊布置方式及覆岩赋存特征，采用理论分析、数值模拟和现场实测等方法，分析了台阶区域覆岩结构运动特征和围岩应力演化规律，研究了台阶区域冲击地压诱发机制。研究结果表明：1304工作面台阶区域覆岩经历了“OX-S-C”型较为复杂的结构演变，覆岩空间结构由OX向S型转换时，顶板岩层大面积破断下沉，在台阶区域形成多个悬臂梁结构，越往高位，悬臂梁长度越大；受覆岩运动和采动应力场叠加影响，煤岩体形成高应力集中区，在顶板岩层动载冲击作用下，煤岩体弹性应变能突然释放，诱发冲击地压。采用COMSOL软件对不同卸压钻孔参数下煤体应变能分布特征进行模拟研究，优化了台阶区域卸压钻孔参数。根据模拟结果，随着钻孔孔径、孔深增大及间距减小钻孔卸压效果越明显，考虑工程实际，确定孔径为150 mm、孔深为30 m、间距为1 m为合理有效的卸压钻孔参数，并应用于1302工作面台阶区域的冲击地压防治，取得了较好的防冲效果。

Mechanism and prevention of pressure burst in step region based on overburden strata movement of unequal length working face

For the problem of pressure burst disaster in step region of unequal length working face in Yangcheng coal, based on the special arrangement mode of working face and overlying strata characteristics, the theoretical analysis, numerical simulation and field measurement are adopted to analyze the dynamic evolution process of surrounding rock stresses and the movement characteristics of overlying, and the mechanism of pressure burst in step region has been investigated. The results show that: the overlying strata in step region experiences a complex evolution of “OX-S-C”, when it is converted from OX to S, large area of roof rock is breaking and sinking, in large area of roof rock, and the higher the height is, the greater the length of cantilever beam over step region is. Influenced by the overlying rock movement and the mining stress field, the coal and rock mass form a high stress concentration area. The coal-rock mass is suddenly destroyed with releasing elastic strain energy under the action of dynamic load of roof rock, and the pressure burst occurs. The strain energy distribution characteristics are investigated by using software COMSOL under different drilling parameters, and the parameters of drillhole pressure relief are optimized. According to the simulation results, with the increases of borehole diameter, depth and decreasing spacing, the pressure relief effect is more obvious. Considering the engineering application, diameter of 150 mm, depth of 30 m and spacing of 1 m are regarded as the reasonable drilling parameters. This method is applied to the prevention of pressure burst in step region of working face 1302 in Yangcheng coal, and good prevention results have been achieved.