Risk assessment and landslide prevention design using numerical modelling — A case study in Qingliu, China

Numerous Quaternary deposits are existed in the mountainous areas of Southwest China, especially in the transition zone between the Qinghai-Tibet Plateau and the Sichuan Basin, where strong tectonic movements and frequent climatic changes increase the potential landslides. The possible deformation and failure process of potential landslides and their impacts on the surrounding environment are important research topics. Field investigation and monitoring indicate that the Qingliu landslide in Xiameng town, Li County, Sichuan Province, China has been continuously deforming since August 2020. The deformation zone has a maximum deformation depth of approximately 18.9 m, a total area of 54,628 m 2 , and a volume of 34.0×10 4 m 3 , which seriously threatens infrastructure projects and dwellings. As a result, understanding the Qingliu landslide evolution process, assessing the hazard risk, and planning disaster prevention measures are of great significance for reducing disaster loss. In this study, the mass movement process and hazard risk of the Qingliu landslide are evaluated, and the effects of different prevention measures are compared and discussed. By using the depth-integrated method, the mass movement of the Qingliu landslide is analyzed. The numerical simulation results indicate that the maximum velocity of the Qingliu landslide is approximately 37.5 m/s, and the duration of the landslide is approximately 90s. The simulated landslide can eventually form a deposited mass with a maximum deposit thickness of 19.4 m and an area of approximately 60,168.3 m 2 , thereby blocking the river and burying dwellings. Furthermore, a risk assessment of the Qingliu landslide under different forms of protection measures is also produced and discussed by considering the hazard level and economic vulnerability level of the affected area. Setting three layers of anti-slide piles on the deformation zone to reduce the hazard risk of the Qingliu landslide is a better choice. Our results may be useful for planning prevention measures and improving disaster emergency response systems.