基于数值模拟的隧道超挖围岩力学响应分析

Mechanical Response Analysis of Surrounding Rock in Over-Excavated Tunnel Based on Numerical Simulation

以曼木树隧道为工程背景,采用数值模拟及现场监测的方法,对围岩等级为Ⅳ级,在不同埋深、不同超挖深度工况下,隧道超挖围岩的力学响应进行了分析。分析结果表明:在同样超挖,不同埋深的工况下,洞壁围岩应力随着埋深的增大基本呈线性增长,洞壁围岩的组合变形量在左拱腰、拱顶、右拱腰等区域均大于左拱脚、右拱脚区域;在同样埋深,不同超挖的工况下,随着超挖的增大,各洞壁围岩的组合变形量在左拱腰、拱顶、右拱腰等区域均大于左拱脚、右拱脚区域;在不同超挖,不同埋深的工况下,超挖40cm时,各个应力问题与埋深无关,超挖60cm、80cm时,水平应力与等效应力问题发生位置与埋深有关,其余应力问题发生位置与埋深无关。

In the paper,replying on the Manmushu Tunnel project,numerical simulation and on-site monitoring methods are used to analyze the mechanical response of the tunnel over-excavated surrounding rock at grade IV,under different buried depths and different over-excavation depths.The analysis results show that under the same over-excavation and different buried depths,the stress of the surrounding rock of the cave wall basically increases linearly with the increase of the buried depth,and the combined deformation of the surrounding rock of the cave wall is in the areas such as left arch,vault,and the right arch where are larger than those of the left arch and right arch;under the same buried depth and different over-excavation conditions,with the increase of over-excavation,the combined deformation of the surrounding rock of each cave wall is at the left arch,vault,right arch waist where are larger than the left arch foot and right arch foot area;and under different over-excavation and different buried depths,when the over-excavation is 40 cm,each stress problem has nothing to do with the buried depth,when the overexcavation is 60 cm and 80 cm,the location of horizontal stress and equivalent stress is related to the buried depth,and the location of other stress issues has nothing to do with the buried depth.