Abstract: The Three Gorges Reservoir area, a region prone to heavy rainfall, is one of the most landslide-prone areas in China. Under the influence of rainfall, dip slopes composed of rock are particularly susceptible to landslides. Statistics indicate that 64% of the massive and large landslides occur in such structural rock bank slope segments, especially those with weak interlayers, posing severe threats to the safety of people and property. [Objective]Understanding the deformation characteristics of these dip slopes and their response to rainfall patterns is of great significance for the construction and operation of the reservoir area. [Methods]This study, using the Shanshucao dip rock slope as a prototype, employed a scaled physical model test method to simulate the entire deformation and failure process of dip rock slopes with weak interlayers under four different rainfall patterns: advanced rainfall pattern, intermediated rainfall pattern, delayed rainfall pattern, and uniform rainfall pattern. The study revealed the evolution characteristics of the stress field and seepage field within the slope and identified the stages of slope deformation and failure. [Conclusion]The research findings indicate that: (1) Different rainfall patterns primarily affect the response time of stress and seepage in the weak interlayer, with minimal impact on the interaction forces within the rock mass. (2) The stress redistribution caused by dip rock slopes with weak interlayers is mainly concentrated in the weak interlayer, with the stress variation being most significant at the toe of the slope. Although the trends of pore water pressure and displacement changes in the weak interlayer are generally similar under different rainfall patterns, there is a significant difference in the initial response time of pore water pressure. (3) Under different rainfall patterns, the landslide failure modes are mainly characterized by overall sliding failure and local sliding-tensile cracking failure. As the rainfall peak shifts forward, the traction-type failure becomes more pronounced. The location of the rear edge of the overall landslide failure is related to the position of the rainfall peak; the further forward the rainfall peak, the further forward the rear edge cracks. (4) Based on the macroscopic deformation characteristics of the slope observed in the physical model tests and multi-field monitoring data, the deformation and failure process of the dip rock slope can be divided into three stages: the deformation stage of the slope's leading edge, the strain accumulation and development stage, and the overall accelerated deformation stage.
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