Investigation on progressive failure process of tunnel lining induced by creep effect of surrounding rock: A case study

Creep of weak rock is an important and challenging consideration during operation of tunnels, since it may lead to failure of tunnel lining with the increase of pressure and the additional deformation. In this paper, the progressive failure process of tunnel lining induced by surrounding rock creep effect was studied through time-dependent numerical simulation. In this numerical analysis, the Nishihara model considering D-P yield criterion compiled by UMAT was used to characterize the creep characteristics of surrounding rock, and the creep mechanical parameters of surrounding rock in the section with serious tunnel lining diseases were obtained by triaxial creep tests. The concrete damaged plasticity (CDP) model was used to represent the damage characteristics of lining. Numerical simulation was verified by comparing with the tunnel displacement monitoring results. It is shown that long-term stability and progressive failure mode of tunnel lining are affected by the creep effect of weak rock. The stress combination dominated by thrust and bending moment in the first 30 years makes the lining concrete unable to maintain stability. The failure modes of lining were divided into early compression damage of arch crown and late tension damage of arch shoulder.

Automated summary

This paper studied the progressive failure process of tunnel lining induced by surrounding rock creep effect through time-dependent numerical simulation. The research found that the creep effect of weak rock affects the long-term stability and progressive failure mode of tunnel lining.