下分层回采巷道帮锚杆支护机理

Support Mechanism of Side Bolts in Lower Slicing Roadway

两帮稳定是保证下分层回采巷道围岩整体稳定的关键.利用非线性有限元数值计算方法,模拟了上分层回采巷道开挖、上分层回采和下分层回采巷道开挖3个阶段.计算结果显示了内错式下分层回采巷道围岩破坏过程和破坏范围;两帮煤壁位移不对称,深部位移是表面位移的主要成分,两帮上侧位移大于下侧位移;帮锚杆主要控制两类破坏面的发展,起到挡土墙的作用.现场实测结果表明,帮锚杆可以有效支护两帮煤体,实验取得了成功.

The stabilization of side coal-walls is the key to guarantee the stability of surrounding rock when the lower slicing method is used. The non-linear finite element analysis method was used to simulate the three stages of 1） the excavation of upper slicing roadway, 2） the mining of upper slicing, and 3） the excavation of lower slicing roadway. The calculation shows the failure process and failure area of the surrounding rock of the lower slicing roadway. The calculation also shows that 1） the displacement of the side coal-walls is unsymmetrical, 2） the deep displacement of roadway is the principal composition of surface displacement, 3） the displacement of the upper side coal-walls is greater than that of the lower side, and 4） the function of side bolts is controlling the development of two kinds of failure planes, similar to the function of a retaining wall. The results of actual measurement indicates that side bolts can effectively support two side coal-walls and so the experiment is successful.