Centrifugal model test and numerical simulation for anaclinal rock slopes with soft-hard interbedded structures

Most of the toppling deformations exposed in western China have soft-hard interlayer structures. The maximum depth even reaches 300 m. In order to further explore the toppling mechanism of soft-hard interbedded anaclinal slope, centrifugal model tests and UDEC simulation are combined. The mechanical mechanism of toppling is analyzed through point-to-point relative displacement. Random fissures are preset in rock plates of numerical slopes, and the evolution laws of failure surface are obtained. The results show that the displacement and fracture morphology of numerical model agree well with physical tests. The toppling process of slope can be divided into initial creep stage, steady deformation stage and failure stage. The front part of the slope is compression-shear composite deformation, while the rear part is tension-dominated. The main fracture surface runs through the whole slope rapidly from the slope toe with a curved shape, and is a tension-shear fracture surface. There are three fracture surfaces in the slope, which can be used as borders to divide the toppling slope into extremely strong toppling zone, strong toppling zone and weak toppling zone. At the anaphase of the deformation, the failure mode of slope toe turns into compression cracking, and the toe rocks gradually separate from parent rocks, leading to the progressive retrogressive failure of slope along different fracture surfaces. The slope is more likely to be damaged when the sum of the dip and slope angle is greater than or equal to 120°. The slope angle mainly affects the damage degree, and the dip controls the deformation scale.