A magnitude of Ms 7.0 earthquake struck the Jiuzhaigou World Natural Heritage Park

in Jiuzhaigou county

Northwest of Sichuan province on August 8

2017

and trigged abundant coseismic landslides deposit in the scenic spot. Due to the heave rainfall after earthquake

the slope debris flow occurred frequently

which seriously threatened the restoration and reconstruction in the after three years. In 2017?2020

continuous investigation

remote sensing interpretation and in-situ erosion test were used to research the impact of slope runoff erosion on deposit. The result shows that the seepage response characteristics are significant during the scouring process

and the downward movement of wetting front causes the increase of volumetric water content and pore water pressure

the matrix suction first fluctuates slightly and then decreases. In addition

the material characteristics of deposit provides the prerequisites for initiation. Under strong hydrodynamic conditions

the startup process is "preliminary penetration → scraping slip flow → rapid accumulation → local saturation erosion-stability". And finally

the mechanical analysis of deposit under different saturations is more consistent with the field test monitoring results. It is further believed that the increase of soil moisture content

and pore water pressure

the rapid decrease of matrix suction and the erosion of high-intensity runoff caused the initiation. The research results can have a certain significance for the long-term effects prediction of debris flow and ecological management after the earthquake.