Study On Dynamic Viscosity Test Of Landslide Soil Rock Mixture

Landslide soil rock mixture is a typical multiphase composite material.During its movement,each phase material is mixed violently,which makes the whole movement state present fluidization characteristics.The dynamic viscosity coefficient is an important parameter to describe the flow characteristics of materials.The dynamic viscosity coefficient is affected by shear rate,water content and stone content.Taking landslide soil rock mixture as the research object,the test method of dynamic viscosity of soil rock mixture is proposed,the dynamic viscosity test of soil rock mixture under different water content and stone content is carried out,and a dynamic viscosity model of soil rock mixture including shear rate,water content,stone content and other factors is developed(1)A test method for dynamic viscosity of landslide soil rock mixture is proposed by combining model test with numerical inversion.Through the model test of landslide dynamic process,the data of displacement change with time in the process of earth rock landslide movement are obtained.The inversion method of combining simplex method and numerical calculation of landslide dynamic process is adopted.The objective function is to minimize the difference between the mass center displacement of landslide numerical calculation and the test data,and the dynamic viscosity model and parameters are obtained.The dynamic change of dynamic viscosity of soil rock mixture during landslide movement can be obtained by this method,which reflects the non Newtonian shear mechanical characteristics of soil rock mixture.(2)The dynamic test system of earth rock landslide is constructed,and the effects of earth rock volume,water content and stone content on the movement characteristics of earth rock landslide are studied.The test system mainly includes three parts: chute test device,video recording device and digital image processing program.This paper analyzes the influence of earth rock volume,water content and stone content on the movement form,centroid displacement and centroid velocity of earth rock landslide,and describes the movement process of earth rock mixture qualitatively and quantitatively.(3)Based on the landslide physical model test data,the power-law constitutive model is selected,and the numerical inversion method is used to obtain the dynamic viscosity model parameters of soil rock mixture.The quantitative relationship between the power-law model parameters and water content and stone content is established,and the influence of water content and stone content on the dynamic viscosity of soil rock mixture is analyzed.The results show that the dynamic viscosity increases nonlinearly with the increase of water content and stone content.(4)In this paper,a dynamic viscosity model of soil rock mixture is developed considering the influence of shear rate,water content and stone content.The model includes three physical parameters.The reliability and applicability of the model are verified by comparing and analyzing the mass center displacement of landslide calculated by model parameters with test data.The model is used to analyze the sensitivity of dynamic viscosity to water content,stone content and shear rate.The results show that the dynamic viscosity of soil rock mixture decreases with the increase of shear rate.When the water content is high,the viscosity of soil rock mixture is more sensitive to the change of shear rate;When the stone content is high,the dynamic viscosity of soil rock mixture changes rapidly with the shear rate.