Centrifuge Model Test Study on the Deformation Evolution of a Soft-Hard Interbedded Anti-Dip High Slope with a Fault

Anti-dip slopes are common in geological environments, and the presence of faults disrupts the integrity of the rock mass, influencing slope failure mechanisms. To study the deformation and evolution patterns of anti-dip slopes with soft-hard interlayers containing faults, a physical model of the slope was made based on the Zhoujia landslide prototype, using similarity theory for material preparation. Through a centrifugal model test combined with particle image velocimetry (PIV) measurement technology, the mechanical response laws, deformation evolution and failure modes of the rock layers in the anti-dip area of the slope model were analyzed. The experimental results show that within the loading range of 20–40 g, internal pressure values in the anti-dip rock layers increased from 23 to 77–85% of their maximum, marking this phase as the primary deformation period for the slope body. The fault exhibited weak mechanical properties and uneven stress distribution, interacting complexly with the anti-dip rock layers, which in turn affected the failure modes of these layers. The deformation evolution of the anti-dip area encompassed three main stages: initial slight bending of the lower rock layers; continuous bending, toppling, tensile fracturing, and rupturing of the rock layers; and reverse bending of the rock layers, accompanied by the formation of multiple failure surfaces. Additionally, PIVlab results demonstrated a correlation between the displacement field and deformation evolution in anti-dip rock layers. This research can provide a reliable reference for deformation evolution models and mitigation measures for high anti-dip slopes with interbedded soft and hard rocks.