活断层错动位移下衬砌断面型式对隧道结构的影响

Influence of Lining Section Type on a Tunnel Structure Under Active Fault Movement

以棋盘石隧道为工程背景,采用有限元方法,设置五种不同仰拱半径的三心圆断面,对比研究了活动断层错动下不同衬砌断面型式对链式结构隧道受力及塑性变形的影响。结果表明:断层错动引起隧道二次衬砌受到拉张、剪切、挤压组合作用;断层错动引起的高应力带主要在断层带内的节段拱脚位置,且峰值位于上盘,剪切缝能有效地吸收断层错动产生的拉应力;在隧道断面不断趋向正圆的过程中,二次衬砌最大主应力、最小主应力、剪应力均呈减小趋势,等效塑性应变呈增大趋势。

Using the finite-element method,this paper compares and studies the influence of lining section type on the stress and plastic strain of tunnels with chain-structures under active fault movement based on five threecentered circular sections of different invert radii from the Qipanshi tunnel project.The results show that：（1） the secondary lining is subjected to the combined action of tensioning,shearing,and squeezing due to fault movement;（2） high stress is mainly distributed at the arch spring with the peak stress on the hanging wall,and tensile force will be effectively absorbed by the shear crack;（3） with the tunnel section constantly tending toward a perfect circle,the maximum and minimum principal stresses and shear stress of the secondary lining decrease while the equivalent plastic stain increases.