ANALYTIC SOLUTION FOR ROCK-LINER INTERACTION OF DEEP CIRCULAR TUNNEL

In order to analyze the plastic evolution characteristic of rock-liner interaction for a deep circular tunnel, the elastic-plastic analytic solution for rock-liner interaction is developed under general loadings，in which the constitutive models of surrounding rock and the liner are the Mohr-Coulomb and bilinear model respectively. Based on the analytic expression, displacement, sensitivity of the displacement and plastic zone of surrounding rock varying with general loading are determined. The results of parametric investigation and example computation show that: 1) provided that the surrounding rock or the liner is transformed from an elastic stage to a plastic stage, the sensitivity of displacements will have a significant change; 2) the sensitivity of displacements varying with positions will be discontinuous in the interface of the plastic and elastic zone; 3) according to the sensitivity of displacements, the stability of a rock-liner interaction system can be decided, and the unstable zone can be defined by the ratio of a critical plastic radius .