双层采空区隧道开挖围岩稳定性数值模拟

隧道下穿煤层采空区开挖不可避免地会对周围地层产生扰动,活化既有采空区,影响隧道及采空区周围地层的稳定性。由于双层采空区的特殊性,采空区与采空区之间也会产生一定的影响。利用FLAC3D软件,通过控制变量法建立双层采空区隧道模型进行计算,考虑采空区高度及采空区之间间距的影响,对隧道开挖过程中围岩形变及位移、围岩应力及围岩塑性区的开展情况进行分析。得出双层采空区存在时,当采空区之间间距大于20倍煤层采高时,双层采空区可按单层采空区进行处理。

Numerical Simulation of Surrounding Rock Stability in Tunnel Excavation beneath Double Mined-out Area

The construction of tunnel beneath coal mined-out area disturbs unavoidably the surrounding rock,activating the existing mined-out area,which affects the stability of tunnel and formations nearby.The neighboring mined-out areas may interact with each other due to their particularities. The numerical simulation of tunnel excavation beneath double mined-out area is conducted with FLAC3 Di software and control variables. In view of the effects of the height and the distance between mined-out areas,the displacement,stress and plastic zone of surrounding rock are analyzed. The results indicate that double mined-out area can be simplified as single mined-out area once the distance between mined-out areas is greater than 20 times of mining thickness.