Theoretical Analysis of Supporting Effect of Rock Bolt in Tunneling Design

Abstract

A theoretical method is presented in this paper to assess the reinforcing effect of grouted rock bolt for rational tunneling design. Based on the Mohr-Coulomb law and strain-softening behavior of rock mass, the rock bolting effect is evaluated quantitatively considering the interaction ofrock mass, rock bolt and other supporters such as shotcrete. The reinforcing effects of rock bolt in the standard supporting pattern of Japan High Way Accociation have been verified. It is found that the reinforcingeffect of the rock bolt is not significant when it is installed in a relatively weak or very good gound condition. The shotcrete can improve the rock bolting effect in a weak ground condition.