Analysis of the Interaction Damage Mechanism and Treatment Measures for an Underpass Landslide Tunnel: A Case from Southwest China

Abstract

Previous studies have analyzed the damage of tunnels and slopes as a single entity, ignoring the interaction effect between the tunnels and slopes, which will have an impact on the accuracy of the damage mechanism and the safety of the treatment measures. In this paper, three types of simulation models are established—the natural state, after tunnel excavation, and after reinforcement measures—considering a case study of an underpass landslide tunnel in southwest China. Based on the theory of underpass landslide tunnels and the strength reduction method, the interaction damage mechanism of this underpass landslide tunnel is revealed, and a reasonable treatment plan is proposed. The analysis results show the following: there is an obvious interaction effect between the tunnel collapse and the slope instability; a large number of mudstones common in the surrounding rock of the tunnel have rheological properties, which amplify the influence of the interaction effect of the tunnel through the landslide; and the proposed comprehensive treatment measures of “rescue inside the tunnel cave + tunnel slope treatment” have strong pertinence and effectiveness, and they fundamentally address the tunnel collapse and the slope instability of the tunnel.