煤层底板采动深度探测与数值模拟研究

Mining Depth Detection and Numerical Simulation on Coal Seam Floor

以某矿41503工作面为研究背景,先后采用理论预计、双端封堵侧漏现场实测、FLAC^(3D)数值模拟等方法,对该工作面采动后底板岩体破坏深度进行研究。研究结果表明:(1)41503工作面采后底板破坏深度理论预计结果为16.89~20.40m,现场实测结果为12.26m,数值模拟结果为13.67m;(2)通过对比发现,现场实测结果与数值模拟结果基本接近,而经验公式预计的结果偏于保守,综合确定该工作面底板最大破坏深度为12.26m,为承压水上安全开采提供依据;(3)数值模拟显示,随着工作面推进,底板塑性区不断增大,当工作面推进至90 m时,底板采动破坏深度达最大值13.67m,此后最大破坏深度不再增加,其破坏顶界沿走向呈一条与底板近似平行的直线,沿倾向大致呈"倒马鞍形",且塑性区变化与最大主应力变化趋势一致。

The failure depth of floor rock was studied after minging the 41503 working face in a coal mine by the methods of the- oretical prediction, field measurement of double ends plugging device and FLAC-Dnumerical simulation.And the results were obtained as follows. Theoretical result of floor failure depth after mining the 41503 working face was 16.89-20.40 m, the measured result was 12.26 m, and the numerical simulation result was 13.67 m. By comparison, the measured result and nu- merical simulation result were basically similar, and the expected result of the empirical formula was conservative. Therefore, the maximum floor failure depth was comprehensively determined as 12.26 m, which provided reference for safe mining upon confined water. Numerical simulation showed that, with the advance of the working face, the floor failure zone was increasing continuously. When the working face was excavated to 90 m, the depth of the floor mining failure was up to the maximum val- ue of 13.67 m. After that, the maximum failure depth would not increase, and its top boundary of failure zone along strike presented a straight line which was approximately parallel to the floor. And along inclination, the shape of the floor failure zone was roughly like＂inverted saddle＂. The change trend of floor failure zone was consistent with that of the maximum principal stress.