Failure mechanism analysis and mass movement assessment of a post‑earthquake high slope

Landslides induced by rainfall pose a notable threat to post-earthquake reconstruction in mountainous areas. Taking Qingliu landslide as an example, this paper reveals the potential failure mechanism and range of the landslide mass through field investigation and monitoring data, and further uses the improved computational fluid dynamics method to simulate and predict the disaster range after landslide destabilization. The results show that the landslide was initially deformed and cracked under the influence of strong earthquakes and formed seepage channels for water infiltration. The circulation of surface recharge of groundwater in rainy season and long-distance recharge of groundwater from melting ice and snow in winter season leads to the continuous softening and reduction of sliding resistance in the sliding zone. Under the action of this change chain, the cracks along the back edge and boundary of the landslide continue to develop and expand and finally will lead to landslide collapse failure. The equivalent fluid method can better simulate the movement process and accumulation process of landslide, since the Qingliu landslide is a soil landslide with fluid characteristics in the process of landslide movement. The results indicate that the maximum speed of the mass flow could reach 49 m/s, which could destroy the infrastructures along the sliding path, besides, both of the two landslides could bury Xiameng town below and block the Mengtun River to form a landslide-dammed lake. The research results could provide a reference for further comprehensive treatment of landslides and the formulation of emergency plans.