Impact and scraping effects of the high-elevation,long-runout "7.23" landslide in Shuicheng , Guizhou

This paper analyzes the Shuicheng"7.23" landslide in Guizhou, 2019. Based on the field survey, Unmanned Aerial Vehicle（UAV） images and numerical simulation, the movement process, and impact and scraping effects of this landslide are characterized. Results suggest that， (1) the Shuicheng"7.23" landslide sliding volume is about 70×104 m3, with the horizontal slide distance 1,360 m, elevation difference 430 m between the front and the toe, and the equivalent friction angle 19°, implying a typical high-level, long-distance slope slide； (2) After the initiation of the slide, it hit the convex ridge, scraped the residual slope soil of the surface, disintegrated and formed a debris flow, resulting in a maximum scraping depth of 11 m； (3) The numerical simulation shows that the maximum velocity of the landslide is 30 m?s-1, the maximum kinetic energy is 8,900 kJ, the scrap volume is 46×104 m3, and the deposit volume is 116×104 m3, with an obvious amplifying effect of hazard； (4) The impact and scraping process of the Shuicheng landslide can be divided into 3 stages, impact insertion, shear nappe and mixed accumulation of sliding debris.