Model test study on sliding-toppling composite deformation evolution of anti-dip layered rock slope

Anti-dip rock slopes are widely developed and distributed in the Three Rivers basin in China, and associated deformation and damage phenomena are especially prominent among slope problems, including composite toppling under internal and external dynamic coupling. Through a model test of similar material, the entire sliding-toppling composite deformation and failure process of an anti-dip rock slope under an external load is studied. The macroscopic deformation, rock displacement, and maximum flexural surface in the process of slope deformation and failure are analyzed, and the composite toppling failure mechanism and evolution law of the anti-dip layered rock slope under various stress conditions are revealed. A physical model is validated by inverting the Zongrong landslide through discrete element numerical simulations, and the anti-dip rock slope with composite toppling deformation is divided. The research results show that (1) block toppling-shear slip damage occurs in the toe area, which is accompanied by the maximum flexural surface, the lower rock layer shows multilayer flexural toppling, the upper rock layer is relatively stable, and the slope is zoned according to the D f value; (2) deep dissection of the river is a precondition of such slope toppling deformation, while rainfall was a predisposing factor for the Zongrong landslide; and (3) the failure mode of the anti-dip rock slope under an external load is generalized into five main stages, shear slip of the slope toe → block toppling of the slope toe → maximum flexural surface → deep flexural toppling of the rock stratum under the flexural surface → penetration of the main fracture surface, and verified using the discrete element numerical model.