基于PFC3D隧道采空区上覆岩层破坏机理研究

本文采用PFC^3D数值模拟软件,结合牡佳客专青龙山小煤窑上覆岩层垮落情况以及孔隙率变化特征,对小煤窑采空区上覆岩层破坏机理进行研究,得出以下结论:上覆岩层由于应力集中和覆岩崩塌引起的冲击作用,工作面底板产生更多裂缝且不断积累和发展,形成贯通性裂纹通道,直至底板裂纹区域深度达到15 m;在工作面推进过程中,工作面上方、后方以及工作面附近孔隙率较大,随着工作面的推进,工作面后方孔隙率大的领域增加,使工作面推进区域上方孔隙率大的领域不断向前发展,形成细长形状,由于上覆岩层的支承作用,两巷附近的孔隙率仍会保持较大值。

Research on Failure Mechanism of Overlying Rock Strata in Tunnel Goaf Based on PFC

In this paper,PFC;numerical simulation software is used to study the destruction mechanism of the overlying rock strata in the Qinglongshan small coal mine goaf in Mudanjiang-Jiamusi Passenger Service,and the overlying strata’s collapse and porosity changes are analyzed.It is concluded that due to the impact of stress concentration and collapse of the overlying rock layer,more cracks will be generated in the floor of the working face,which will accumulate and develop cracks,forming a permeable crack channel until the depth of the crack area of the floor reaches 15 m;during the advancement process of the working face,the porosity above,behind and near the working face is relatively large.As the mining advances,the area with large porosity behind the working face is increased,and the porosity above the advancement area of the working face is increased.Large areas continue to move forward,forming a slender shape.Due to the supporting effect of the overlying rock strata,the porosity near the two lanes will still maintain a relatively large value.