UAV survey and numerical modeling of loess landslides: an example from Zaoling, southern Shanxi Province, China

This work attempted to reveal the geometric and kinematic characteristics of a loess landslide that occurred at Zaoling, southern Shanxi Province, China, on March 15, 2019. Based on the high-resolution unmanned aerial vehicle survey and DEM data acquired after this event, the topography of the study area was reconstructed to estimate the volumes of the source area and the deposit area of the landslide. Coupled with the high-resolution three-dimensional topographic data, three-dimensional particle flow code was used to simulate the motion process and depositing characteristics of the landslide. Results show that the Zaoling landslide is a deep-seated loess landslide with a projection area of 9844 m(2)and the attitude of the sliding surface 355 degrees angle 37 degrees (trending and dip). The total volumes of the source zone and accumulation zone are 77,000 and 82,000 m(3), respectively. The simulation results show that the whole sliding process lasts about 17 s. The maximum average velocity of the sliding body is 5.12 m/s and the average sliding displacement is 33.3 m. Comparing the depositing thickness obtained from the simulation with the reality shows that the accumulation thickness of the deposit area decreases gradually from the center to both sides. The accumulation characteristics from the simulation are roughly consistent with those of the actual landslide. According to the latest landslide classification system for loess slopes, the Zaoling landslide is a typical rotational slide. It is a typical case for loess landslide studies, in particular, its special failure mechanism and kinematic features.