Study On Scraping Mechanics And Dynamic Characteristics Of Landslide-debris Flow

The scraping effect is common in the movement process of landslide-debris flow,which is the impact and shear action of debris body with the base sediment.The base sediment is scraped by the slide body,resulting in the increase of the volume of the slide body,and it is affected the movement and accumulation characteristics of landslide debris fluid.In this paper,the physical model tests and the numerical simulations was used to study the mechanics and dynamic characteristics of scraping effect.After experimently and numerically investigation at different situation of the landslide scraping effect,it analyzed the mechanical evolution and dynamic characteristics of the interaction between the debris body and the substrate and revealed the influence of scraping effect on dynamic characteristics of landslide-debris flow,and combined with the existing theoretical models for comparative analysis.This study is beneficial to further study the dynamics of landslide debris flow,and can provide important reference and theoretical basis for landslide debris flow planning,prevention,and risk assessment.Through the self-designed model test,the scraping force of the scraping effect is monitored,and the mechanical mechanism and dynamic characteristics of the scraping effect are analyzed.The results show that different types of base materials significantly affect the scraping effect mechanism and mechanical behavior.Formation is the result of the combined impact of the leading edge of the landslide debris body and the bottom shear.The effects of the volume of the sliding source area,the bonding strength of the scraping area,and the scraping speed on the scraping force and scraping dynamic characteristics were analyzed by numerical simulation.The bonding strength of the scraping area had a small effect on scraping force.But the greater the bonding strength,the smaller the landslide debris flow's speed and scraping amount;the volume of the sliding source area and the distance between the scraping area and the sliding source area significantly affect the magnitude of the scraping force and its dynamic process.Shows a positive correlation with shovel scraping force.Finally,comparing the scraping force of the model test and numerical simulation monitoring with the scraping force of the more theoretical model Frictional model and Voellmy model,the results show that the Frictional model does not consider the dynamic characteristics of debris flow,which the calculation result of the scraping force is small,and the Voellmy model is usually too large due to the uncertainty of the turbulence coefficient.Therefore,it is necessary to carry out further research and establish a new mechanical model of landslide debris flow scraping effect.