Numerical simulation of the effect of geostress on large deformations of deep soft rock tunnels

摘要

There exist two types of finite deformation theorems in large deformation process of deep soft rock engineering, i.e. polar decomposition theorem and additive decomposition theorem. In this paper, referring to the functional expression between geostress and the depth proposed by Brown and Hock, the additive module and the polar decomposition module included in A Software on Large Deformation Analysis for Soft Rock Engineering (LDEAS) at Great Depth were adopted respectively to simulate the effect of geostress on the large deformation induced in the process of the excavation of Jia-he Mine at 800 m level. The results indicate that: the sidewall shrinkage, floor heave and roof caving represent a positive linear relationship with the depth and the increasing rate of the mount of floor heave is the fastest. Moreover, the mount of the deformation calculated by solar decomposition module is relatively smaller than the corresponding result obtained through the polar decomposition module.