抄録
The Minxian-Zhangxian Ms6.6 earthquake induced a large number of loess landslides and collapses on July 22, 2013 in Dingxi city, Gansu province. In the center of the quake-hit area, it caused a banding area of landslides dense distribution with 8km wide and 30km long, and which long axis direction is in accordance with the trend of seismo-tectonics of the earthquake. Based on field test pit survey and surface wave investigation, the topography and soil distribution of the west loess landslide at Yongguang village in the landslides dense distribution area was identified. Moreover, the liquefaction probability of loess of the landslide was proven through dynamic triaxial liquefaction tests. The dynamic response characteristics of the landslide were analyzed by combining dynamic finite element method and strength reduction method as well. The results indicate that continuous heavy rain before the earthquake induced moisture content increasing and shear strength reducing in the surface loess layer of the slope. Coupling with the strong quake, tensile stress and liquefaction occurred in the surface soil layer, which caused the loess slope collapse instantaneously and a sliding distance of about 1000m long.
