Geohazard effects of the Xianshuihe fault and characteristics of typical landslides in western Sichuan

With the geological hazard effect of the active fault as the main study object and on the basis of the development and activity characteristics of the Xianshuihe fault, geo-hazards distribution characteristics, typical geohazards characteristics and stability analysis and other aspects, this paper deals with the geohazard distribution characteristics and formation mechanism of main typical big landslides. The findings indicate that the Xianshuihe fault exerts significant controlling effect on landslides: ①the rock is of highly broken along the fault zone, resulting in zonal distribution of landslides along the fault, and about 32.5% of the geohazards are developed less than 0.5km from the fault zone, 19.77% developed 0.5~1.0km from the fault zone, and 15.22% developed 1.0~1.5km from the fault zone, with the landslide sliding direction mainly perpendicular to the fault; ②Bamei soil-stone forest is composed of shattered rocks formed under the faulting effect, characterized by low rock mass mechanics strength, poor stability and high landslide development density; ③the seismic landslides are well developed in the fault zone, some landslides slide thoroughly in the earthquake and show good stability; some landslides are partially in crack-sliding state formed in the earthquake, and are likely to slide under some external force; ④under the sustained activity of the fault, the slopes or the ancient seismic landslides penetrated by the fault are in poor stability and might experience several times of activities; ⑤to a certain extent, the heavy rain could accelerate the fault slope deformation and increase the frequency of geohazards.