基于损伤变量的煤层底板采动破坏深度计算

Floor failure-depth calculation under mining based on damage variable

传统采动破坏深度计算中认为底板结构完整,未考虑实际岩体损伤。以淮南潘北矿11113工作面A组煤开采为背景,利用FLAC3D对完整与损伤底板采动应力变化特征进行了分析,推导并计算了底板岩层损伤变量与底板破坏深度。此外,为验证该方法的有效性,对比分析了计算结果与测量结果。结果表明:采动应力的最大值出现在煤壁前后方,底板完整时为14.8 MPa,底板损伤时为17.5 MPa;底板岩层损伤变量D为0.574,基于损伤变量计算得出的底板最大破坏深度为16.15 m,对比并行电法探测结果 16.00 m,该方法的计算准确率高。研究结果为快速准确确定底板采动破坏深度提供了一个新思路。

In the traditional calculation of mining failure depth, it is considered that the floor structure is intact and the actual rock mass damage is not taken into account. Taking the Panbei mine working face 11113 as the background, the integrity and damage of floor mining stress changes were analyzed by FLAC3 D. The damage variable of floor rock and the failure depth of bottom plate were deduced and calculated. In order to verify the effectiveness of the method, the calculation results were compared and analyzed with measurement results. The results show that the maximum value of the mining stress appears in the front and rear of the coal wall. When the floor is intact, it is 14.8 MPa, and it is 17.5 MPa when the floor is damaged. The damage variable of the floor rock is 0.574. Based on the damage variable, the maximum failure depth of the floor is 16.15 m. Comparing the results of parallel electrical prospecting of 16.00 m, the method is accurate in calculation. The research results can provide a new idea for determining the failure-depth of the floor mining rapidly and accurately.