单洞双层隧道围岩力学特性分析

单洞双层隧道作为一种新的隧道形式，不同于分离式隧道和连拱式隧道。利用ANSYS对单洞双层隧道和分离式隧道开挖后围岩的情况进行数值模拟，分析开挖后围岩的应力和位移变化情况、塑性区分布和安全系数，通过对比得出：在浅埋情况下两种隧道围岩应力和位移分布基本一致，地表沉降和分离式隧道相当；单洞双层隧道对围岩扰动深度较大，边墙是其薄弱部位，应力松弛明显，水平位移较大，塑性区水平方向分布较大。

The Mechanic Property of Surrounding Rock about Single Cavern and Double Layer Tunnel

As a kind of new structure form,the single cavern and double layer tunnel is different from the separated tunnel and double-arch tunnel. With the general-purpose finite element software ANSYS, the condition of the surrounding rock of the excavation of the single cavern and double layer and separated tunnel is numerically simulated. The change of plastic zone, displacement, stress of surrounding rock and safety factors are analyzed. The results show that the displacement and stress of single cavern and double layer tune is approximately same with the separated tunnel in low deep, and the sedimentation is approximately equal. The single cavern and double layer tunnel is of more influence on the surrounding rock. Sidewall is the especial danger area, and stress relaxation, horizontal displacement and the distribution zone are larger.