Evaluation of Susceptibility to Rocky Landslide in Soft Metamorphic Rock Area Based on Failure Mode of Slope Instability

Abstract:

The landslide is controlled by the geological environment conditions and the geological structure of the slope. There are differences in the pattern of slope instability of different geological structures. Take Houlongmenshan phyllite rock area as an example, based on the field investigation, the relationship between the mechanical model of the rocky landslides in this area & the slope geological environment and the slope structure is summarized, and then select key factors which control the occurrence of landslides, such as slope structure, slope gradient, and slope surface morphology, etc., and use the weighted stack function of ARCGIS software to quantitatively classify the landslide-prone areas of different models. The main understanding are achieved. （1）The phyllite is a layered soft rock. There are 3 types of landslide: “the sliding-tension cracking model”, “the creep-bending model” and “scale toppling model”. “The sliding-tension cracking model” mainly occurs at a slope of 30°～45° where rock dip more than slope. “the creep-bending model” occurs within the slope of 30°～45° where rock dip less than slope, and “the scale toppling model” occurs in the reverse slope where the rock dip is more than 65°. (2)The overlay analysis based on ARCGIS software showed that: the area of “the scale toppling model” area in the zone is 8.73km2, the area of “sliding-tension cracking” area is 4.31km2, the area of “the creep-bending model” area is 3.28km2, and the landslide type is dumped. The result of the comparison of landslides and areas with high incidence of landslides has proved that the landslide-prone areas basically agree with the actual conditions.