Study On The Motion Characteristics And Disaster-causing Effects Of Landslide Under The Action Of Graded Sand And Rough Sliding Plane

In order to study the influence of particle size grading of sliding body and roughness of sliding plane on landslide movement.This paper uses the fluidity of dry and loose sand to conduct indoor direct shear test and slope simulation plate test of dry sand body,and discusses the influence of sand body with different coarse sand content and roughness on the test results.Firstly,direct shear test was carried out to explore the mechanical behavior mechanism between the rough surface material and sand body in shear by interface shear test.T hen,a 3D scanner was used to record the whole process of the landslide simulation inclined plate test,record and analyze the movement process of the sliding body and the stagnation state,and study the change rule of the sliding body motion characteristic parameters under different test conditions.Finally,from the perspective of mechanics,the effects of the properties of the sliding body and the roughness of the sliding surface on the movement process of the sliding body and the packing morphology of the sliding body were analyzed.Finally,a calculation model of the farthest dispersion distance of coarse particles in the slide based on the coarse particle content of the slide and the relative roughness of the slide surface and the relationship curve of the coefficient of apparent friction is established.This paper mainly draws the following conclusions:(1)With the increase of normal stress in the direct shear test,the shear strength increases along with the increase of the strain of it,and the normal stress has a certain inhibitory effect on the dilatancy of sand body.The content of coarse sand in the sand body also has a certain influence on the shear mechanical properties.The analysis shows that a small amount of coarse sand particles weaken the overall strength of the medium and fine sand body.(2)3D scanner was used to record the test process of inclined plate,and it was analyzed that particle sorting was caused by the collision between sand particles and contact surface materials and the interaction between particles in the sliding process.(3)Based on eigenvalue deposit form and sand body of coarse particle content(w)and relative sliding surface material roughness(Rr)friction coefficient is analyzed.It was found that the accumulation length,width and farthest sliding distance of coarse particles in the main body of the pile showed a certain variation pattern with the change of coarse sand content and relative roughness.(4)According to the law of conservation of energy and the test data,the relation formula of the maximum movement distance L suitable for the test mixed sand body and the content of coarse sand and the relative roughness of contact surface Rr was established.The relationship curve of apparent friction coefficient,us obtained by the derivation of equation is in better agreement with the experimental results and is better applicable to the actual landslide.