浅埋软岩隧道开挖围岩变形非线性模拟分析

Analysis on the Non-linear Numerical Imitation of surrounding Rock Deformation During Shallow Overburden Tunnel Excavation within Soft Rock

由于隧道施工过程和开挖顺序的不同都会引起各自不同的应力和应变的非线性历程,最终导致不同的力学效应,特别是软弱围岩隧道,其力学效应表现的更加显著。结合沿海地区软弱围岩浅埋暗挖矩形隧道施工,使用有限差分软件(FLAC)对分部开挖进行非线性数值模拟,研究矩形隧道软弱围岩在开挖过程中大变形的机理。分析结果表明,围岩和初期支护的应力应变是非线性不可逆过程,其开挖方案应采用软弱围岩非线形大变形力学设计方法,以确保开挖施工安全。

The mechanical behavior and deformation characteristics of surrounding rock is different with different excavating method and excavating sequence of large section cavern within soft rock. In this paper, with the rectangle tunnel construction in the foreland soft rock with shallow overburden, FLAC is adopted to simulate the excavation of tunnel using partial excavation method, The mechanism of large deformafion process of rectangular tunnel primary support is studied. The analysis results have shown that lin the excavating process the tunnel surrounding rock and primary support stress and strain, is a non- linear irreversible process.