A MODEL OF THE TIME-DEPENDENT INTERACTION BETWEEN ROCK AND SHOTCRETE SUPPORT IN A TUNNEL

Abstract

A viscoelastic model is developed to simulate the tunnel-support interaction of a circular tunnel in a viscoelsatic rock mass. This model accounts for the time-dependent stiffness and the yielding strain of shotcrete support. This model is formulated to analyze the effects of the time -dependence of support characteristics on tunnel convergence, support pressure, and tunnel-support interaction. Results of a parametric study reveal that the time-dependence of shotcrete stiffness has a strong influence on tunnel convergence and support pressure. Ignoring the yield strain of shotcrete may lead to the underestimation of tunnel convergence and the overestimation of the ultimate capacity of shotcrete support.