Effect of bedrock slope angle on deformation and failure of overlying rock-soil mixture: Insight into the evolution of landslides

The slope angle of bedrock surface plays an important role in deformation and failure of the overlying rock-soil mixture (debris). Therefore, it is of great importance to quantify the effect of bedrock slope on the evolution of landslides in order to obtain a comprehensive evaluation of the mechanical behavior and stability of landslides; however, such quantitative studies are currently lacking. To address this gap we carried out an experimental study on deformation and failure of rock-soil mixture under different slope angles of the underlying bedrock using a home-built large size push-shear apparatus. The results show that with increasing slope angle the included angle between the shearing and bedrock surfaces increases, and so does the distance between the two surfaces. At 25° inclination the overall movement of the rock-soil mixture in the shear zone is most stable; whereas at 45° inclination occurs the most serious debris rupture in the shear zone while the overall movement of debris is most unstable, and the slip zone is most difficult to manage. With increasing slope angle, the maximum shear stress first increases and then starts to decrease at 45° inclination-at this point, the maximum shear stress reaches maximum in the deformation process, and the peaking time of pore-water/soil pressure changes (from their initial values) reach maximum as well. The results and parameters obtained in this study provide a reference basis for evaluating landslide stability and other geological hazards based on the determination of bedrock slope. © 2023 Science Frontiers editorial department. All rights reserved.