Experimental study on rock avalanche runout distance based on CHLT model

Rock avalanche as one of the common geological disasters in mountainous areas, has a movement distance that is closely related to the damage degree of water resource project at the slope foot.To calculate and predict the runout distance of rock avalanche, taking the rock avalanche event that occurred in Su Village, Suichang County, Zhejiang Province on 28 September 2016 as an example, a Catchment-scale Hydro-mechanical Landslide Triggering (CHLT) model was designed.Flume experiments were conducted under various conditions, such as different inclination angles (α, β) of flume slopes, different particle-graded materials and different friction coefficients of the flume bottom, to observe the fluid motion state and accumulation of the rock avalanche during its movement process.Moreover, the influence of different factors on the runout distance of rock avalanche was analyzed by regression method.The results showed that the friction coefficient of flume bottom plate had a significant negative correlation with the movement distance of landslide debris flow, and the correlation coefficient R2 of the fitted curves exceeded 0.82.As the friction coefficient increased, the runout distance of rock avalanche decreased gradually.If there were large particles in the sliding body, large particles collided with the accumulation body in a gentle area, causing jumping and increasing the runout distance of rock avalanche.The research results are of great significance for disaster risk assessment and mitigation of water resource projects.