Performance and application of a novel drainage anti-slide pile on accumulation landslide with a chair-like deposit-bedrock interface in the Three Gorges Reservoir area, China

More than 5000 landslides with different kinds of deposit-bedrock interface morphologies developed in Three Gorges Reservoir area (TGR) after its first impoundment. In this paper, the Outang landslide, a typical accumulation landslide with a chair-like deposit-bedrock interface (CLDBI) located in the Three Gorges Reservoir area (TGR) of China, is taken as an example. More than 6 years of multi-technique monitoring data shows that cumulative displacements over time present a step-like pattern, characterized by the gradual increasing of total displacements with altitude. The factors affecting the slope movement at the upper and the lower parts of the landslide are rainfall and reservoir water, separately. In this work a novel drainage anti-slide pile (DASP) is proposed, and the drainage performance of this DASP is verified and studied through physical model test. To this aim, three different environmental scenarios have been simulated by ABAQUS to evaluate the reinforcement effect induced on the landslide when using the proposed DASP. The model revealed that the optimum solution for the stabilization of the slope consists in the construction of single-row DASPs in the upper part of the landslide. These results provide practical experience and enlightenment on common measures to landslide prevent in TGR using the DASPs.