ELASTIC-PLASTIC ANALYSIS FOR SURROUNDING ROCK OF PRESSURE TUNNEL WITH LINER BASED ON MATERIAL NONLINEAR SOFTENING

摘要

According to the strain nonlinear softening constitutive model of practical rock, pressure tunnel with liner is analyzed. The model is considered the influence of intermediate principal stress σ2. Stress distribution laws of surrounding rock plastic zone of tunnel, the mechanism of load bearing and acting relation between surrounding rock and support are studied. Some important conceptions of working status of practical tunnel surrounding rock are obtained: such superior certain limit [Smax] of self-support geo-stress and inferior certain limit [Smin] of supportless tunnel surrounding rock. The relations between [Smax] and geo-stress, between [Smin] and geo-stress are given. Calculation shows that the assumed mode1 agrees well with practical condition of rocks. Analysis shows that the ideal plastic model and the brittle model are special cases of the proposed solution.