层状复合顶板巷道稳定性分析

Analysis of Tunnel Stability on Complex Layered Structure Roof

采用ANSYS有限元计算模型对层状结构岩层巷道开挖施工进行了弹塑性二维分析,发现巷道底板和煤帮中点位移随着巷道宽度的增加而增加,增加基本按照线性规律,增加幅度比较平缓,即底板和煤帮中点的位移对巷道宽度的变化不敏感.同时对巷道上部层状顶板建立两端固支的力学模型,得到巷道顶板下沉的解析解,由此研究不同高跨比的围岩变形、应力变化模式和破坏特征,对层状岩层巷道的安全评价和支护有一定的指导意义.

The excavation construction of stratified rock tunnels is analyzed by ANSYS finite element model. The results indicate that displacement of tunnel floor and wall midpoint increase with increasing the width of tunnel,which increases nearly linearly and the increase extent is not distinct. The displacement of tunnel floor and wall midpoint is not sensitive to the variation of tunnel width. The analytical solution of tunnel subsidence is obtained when the mechanical model of upper rock fixed at both sides of the tunnel roof is set up, from which wall rock deformation, stress patterns and failure characters with different ratios of depth to span are studied. It has useful instruction for safety evaluation of layered rocks and tunnel supporting.