Coordinated evolution and mechanism characteristics of the tunnel-landslide system under rainfall conditions

In order to study the co-evolution mechanism of the tunnel-landslide system under rainfall conditions, various factors inducing slope deformation and failure process were characterized through field investigation and engineering geological analysis methods based on actual engineering cases. Through the indoor physical model test, the soil pressure and internal force response characteristics of different sections of the tunnel under rainfall conditions were analyzed, and the co-evolution mechanism and disaster model of the tunnel-landslide system were elucidated. The results show that there are regional differences in the failure parts of the slopes under the influence of rainfall infiltration. The sliding force of a slope is less than the long-term strength σ∞ of a sliding zone soil, which is an important indicator of the safety and stability of the tunnel-landslide system. The axial forces in the tunnel are mainly compressed by the sliding of the shallow slope. The difference in bending moment values between the left and right sides of the tunnel in the entrance area is 2.4 times, forming a typical bias tunnel. The tunnel model and the slope are well correlated in the field of deformation, that is, the tunnel model and slope have a common deformation effect. The deformation and failure of the tunnel model are the results of multiple forces coupling, which is highly consistent with the actual situation in the field. These results help us to provide a theoretical basis for the optimal design of tunnel structures in landslide areas.