隧道开挖对上覆煤层采空区地层的扰动分析

摘要

The tunnel construction adjacent to the overlying mined-out area is easy to expand the rapping range of the overlying rock and increase the loose load.In order to study ground disturbance induced by tunnel construction,numerical analysis software of PFC was used to analyze the characteristics of the stress change of the overlying strata during the process of tunnel excavation from the meso-level.The results show that the particle contact force discontinuity region of the surrounding rock is distributed mainly in the upper part of the tunnel during the process of tunnel excavation in overlying mined-out area.The greater the convergence of tunnel inner perimeter is,the greater the particle contact force discontinuity region.The smaller the pitch is,the larger the particle contact force discontinuity region.The thicker the coal seam is,the larger the particle contact force discontinuity region.The dip angle of coal seam has certain effect on the position of loose region.%隧道近接上覆采空区地层施工易扩大上覆围岩松动范围,增大松动荷载,为探明隧道开挖对上覆采空区地层的扰动规律,采用离散元颗粒流软件从细观角度分析了隧道开挖过程中上覆采空区地层应力变化特性,分析了采空区与隧道间距、采空区厚度及倾角对围岩应力的影响.结果表明:上覆采空区地层隧道开挖后围岩颗粒接触力链断开区域分布在隧道上方,开挖后洞周位移越大,颗粒接触力链断开区域也越大;间距越小,开采煤层越厚,颗粒接触力链断开区域越大;煤层倾角影响了松动区域位置.