采动底板附加应力计算及其应用研究

Computation of Mining Induced Floor Additional Stress and Its Application

为了研究煤层采动后的底板应力分布规律和变形破坏规律,利用弹性理论,以应力增量的形式,采用数学分析软件MATHCAD求得底板下任一点的附加垂直应力、水平应力以及剪应力.绘制了底板附加应力分布云图,并根据摩尔库伦准则,将求得的附加应力换算成主应力,代入岩石强度指数进行底板破坏深度预测,且用水力测试法对桃园煤矿1022工作面底板破坏深度进行了现场测试.计算结果表明:在工作面煤壁附近区域,附加应力集中,其值随着底板深度的增加而逐渐减小,由理论计算出的底板破坏深度数值与现场实测数值误差为12%,可靠性比较高.这可为带压开采下煤层突水的治理提供理论依据.

In order to study the stress distribution and deformation law of the floor after the coal seam is excavated,using the elastic theory in the form of increment,we obtain the additional vertical stress,horizontal stress,and shear stress of any point through the MATHCAD software.The distribution map of additional stress of the floor is drawn.According to Mohr-Coulomb criterion,the additional stress is converted to principal stress,then the failure depth of the floor is predicted with the introduction of the rock strength index and the failure depth of 1022 working face in Taoyuan coal mine is in-situ tested with the hydraulic test method.The results show that the additional concentrated stress near the coal wall decreases gradually with the increase of the depth of floor,and the failure depth of the floor computed is 12% different from that obtained in the in-situ test,showing a high reliability of the theoretical computation.The results in this paper can provide a theoretical basis for the control of water-inrush in the coal mining under pressure.