Failure Mechanism of Sandy Soil Slopes Under High-Angle Normal Bedrock-Fault Dislocation: Physical Model Tests

Bedrock fault dislocation is a crucial structural factor influencing landslide movement. Accurately predicting the location and scale of rupture zones within a slope body is essential for effective slope construction design and risk mitigation. Based on an analysis of seismic damage in slope cross-bedrock faults, this article creatively realizes the physical model test of the slope and its covering layer site with soil rupture zones at the top and toe of the slope caused by the dislocation of the bedrock normal fault. Through the model test, macroscopic phenomena were observed, and microscopic analysis was obtained by deploying sensors. The main results were as follows: (i) The evolutionary process of the instability mechanism could be divided into three stages: crack damage stage (Stage I), crack expansion and penetration stage (Stage II), and slope instability stage (Stage III). (ii) Two rupture modes of the soil body in the slope under bedrock dislocation were identified, with the rupture mode at the slope crest having a greater impact on the soil slope. (iii) Inferring the position of bedrock faults through the location of the main rupture zones on the slope surface represents a feasible supplementary method for identifying seismogenic structures during field surveys. These research results provide a scientific basis for the stability assessment of cross-fault slopes and the reinforcement design of landslide disasters.