The substrate of rock avalanche bears severe ploughing and erosion effect during the depositing process of rock avalanche. Firstly

characteristics of the substrate-ploughing and esrosion are described and compared with each other. Then the calibration and verification of particle flow method are carried out

and multiple numerical rock avalanche depositing tests based on this method are done. Test results reveal that both the substrate ploughing and esrosion effect can enhance the runout ability of rock avalanche moving on a horizontal substrate. The influence of substrate materials are also studied by doing numerical tests. The results indicate that smaller strength of the substrate materials leads to more intensive ploughing and erosion effect

however

it seems that

the characterstic of lower strength and lower density of the substrate’s surface material is the key factor of enlarging the runout ability of rock avalanche

this fragile layer serves as lubricant in the base; in contrast

the strength of the underlying substrate material gives no contribution on the avalanche’s runout ability.