Mechanical properties of the combined medium-diameter anti-slide piles and tunnels under landslide loads at different sliding zone angles

Abstract

Abstract The interaction of landslides and existing tunnels in the field of geotechnical engineering is currently a hot research topic. This paper introduces a novel combined medium-diameter pile support system for existing tunnels. The main objective is to investigate the accumulation landslide tunnel as a prototype. The study examines the deformation characteristics of both the existing tunnel and the combined medium-diameter pile support system through a combination of model tests and numerical simulations. The following conclusions were obtained: As the angle of the sliding zone increases, the deformation of the pile body and the tunnel lining structure gradually decreases, leading to a reduction in both earth pressure and bending moment values. When the angle of the sliding zone is ≤ 30°, the horizontal thrust from the landslide has a significant impact on the tunnel lining structure. However, when the angle of the sliding zone >30°, the influence of the horizontal thrust decreases significantly, while the proportion of vertical load on the arch foot gradually increases. Factors such as pile spacing, pile type, and anchorage depth were analyzed through numerical simulation. The findings suggest that for sliding zone angles ≤ 30°, the primary concern lies in the impact of the landslide’s horizontal thrust on the tunnel structure. Conversely, for angles >30°, the attention shifts to the effects of the vertical load induced by the landslide body on the tunnel lining structure.