采动与隐伏断层双重作用下底板破坏特征

针对工作面底板含隐伏断层条件下底板水害多发的问题,综合数值计算与现场实测2种方法探究底板岩体采动破坏特征。模拟结果得出:底板塑性区范围随工作面推进距离增加而扩大,距底板隐伏断层远场的完整型底板岩体最大破坏深度约为18 m,靠近底板隐伏断层的岩体最大破坏深度约为28 m,隐伏断层活化是促进底板破坏深度增加的积极因子;受隐伏断层存在的影响,底板岩体采动破坏范围呈现出以过隐伏断层顶部竖轴为对称轴的正"八"型破坏形态;钻孔窥视实测得到采动破坏影响范围内呈现出裂缝贯通型"环形"破坏圈的特征,底板采动破坏深度最大值约为29 m。结果表明:受隐伏断层和采动应力影响,底板破坏深度明显增大,且扩展路径沿着隐伏断层顶部斜向下发展,数值模拟与实测结果误差约为3.4%。

Characteristics of floor failure under the double action of mining and hidden faults

Aiming at the problem of frequent occurrence of floor water damage under the condition that the floor has hidden faults,two methods of comprehensive numerical calculation and on-site measurement are used to explore the characteristics of floor rock mass mining failure. The simulation results show that the range of floor plastic zone expands with the increase of the working face advancement distance. The maximum failure depth of the intact floor rock mass far away from the bottom floor hidden fault is about 18 m, and the maximum failure depth of the rock body near the bottom floor hidden fault is about 28 m. The activation of the hidden fault is a positive factor to promote the increase of the floor bottom depth;due to the influence of the presence of hidden faults, the mining failure range of the floor rock mass exhibits a positive "eight"type of failure form with the vertical axis at the top of the hidden fault as the symmetry axis;borehole peep observations show that the fracture penetration type appears in the affected area of mining failure. The characteristic of the"ring-shaped"failure circle is that the maximum mining failure depth of the floor is about 29 m. The results show that: under the influence of concealed faults and mining stress, the failure depth of the bottom plate increases significantly, and the extension path develops obliquely downwards along the top of the concealed faults.The error between the numerical simulation and the measured results is about 3.4%.