顶板冲击荷载作用下锚网支护巷道变形破坏规律研究

Study on deformation and failure law of bolt-mesh support roadway under roof impact load

为研究顶板冲击荷载作用下锚网支护巷道的变形破坏规律,以华亭煤矿250104运输巷为背景,采用FLAC^(3D)分析了不同冲击荷载波速、角度以及偏轴距条件下锚网支护巷道围岩的应力、变形以及塑性区变化特征。研究结果表明:顶板冲击作用下,巷道顶板及两帮岩体塑性区将向上方及两侧逐渐扩展,且其最大位移呈指数衰减式增长;随顶板冲击荷载波速增大,巷道周边岩体最大位移呈指数递增式增大;随顶板冲击荷载角度增大,巷道顶板及两帮最大位移呈“S”形增长变化,冲击角度为90°时对围岩稳定性最不利;随顶板冲击荷载偏轴距增大,巷道顶板及冲击侧帮部岩体最大位移出现先增后减的变化规律,冲击偏轴距等于5.0 m时对巷道安全威胁最大。

In order to study the deformation and failure law of bolt-mesh support roadway under roof impact load,taking 250104 transport roadway of Huating Coal Mine as background,FLAC^(3D) was used to analyze the variation characteristics of stress,deformation and plastic zone of surrounding rock of bolt-mesh support roadway under different impact load wave velocities,angles and offset distances.The results show that:under the impact of roof load,the plastic zone of roadway roof and rock mass on both sides will gradually expand to upward and both sides,and its maximum displacement will increase exponentially;with the increase of the wave velocity of the roof impact load,the maximum displacement of the roadway roof and two sides will gradually increases exponentially;with the increase of impact angle of roof impact load,the maximum displacement of the roadway roof and two sides presents an“S-shaped”growth curve,and the impact angle of 90°has the most adverse impact on the stability of the surrounding rock of the roadway with bolt-mesh support;with the increase of the impact offset distance of roof impact load,the maximum displacement of roadway roof and impact side rock will increase first and then decrease.When the impact offset distances is equal to 5.0 m,it will pose the greatest threat to roadway safety.