Numerical Experiment Research Of Solid-fluid Transformation Criterion Of Debris Flow Sliding Process

Flow-like landslide usually triggered by heavy rainfall,The occurrence of flowlike landslide is usually happened suddenly and violent,besides it will cause great damage to our daily life,the safety of our lives and property.So it is necessary for us to research this kind of disaster.The research on landslides has been a long time,the methods of the research always are about landslide model test and numerical analysis model.For the method of numerical simulation,due to the difficulty of mesh method to deal with the problem of large deformation of landslide,The SPH method,which is mesh-less method,has been applied to deal with the problem of landslide,and the result is very well.But the method of SPH always treat the landslide as a pure flow state or a pure solid state,so this paper will research the solid peculiarity and the flow-like phenomenon during the landslide moving.This paper present two numerical simulation methods which are all based on the SPH method,one of the methods is to establish a coupling model which combines the D-P solid constitutive with the Binham fluid constitutive by the transformation criterion of the solid-fluid to,the other one method is to establish a coupling model will combine the modified Mohr-Coulomb solid constitutive with the Binham fluid constitutive by the transformation criterion of the solid-fluid.And each of which will be applied to simulate the Dashuchang landslide of the Fengjie County of Chongqing city.Besides,the result of the two coupling model will contrast with the field data of landslide and the results of other analytical methods,then to verify the viability and effectiveness.And this paper put forward a concept of flow-like rate in order to study and analysis the movement of the flow-like landslide by the coupling model.Finally,the result verify the rationality and effectivity of the transformation criterion of the solid-fluid.Following is the main content of this paper:Firstly,it is based on the Dashuchang landslide of the Fengjie County of Chongqing city,establishing a landslide model test of the transparent soil by using the transparent quartz sand and white oil which is in the same refractive index as the test material.Taking the volume and slide height as the variables,and analysing the law of the movement of the landslide test through the velocity,displacement and the rate of the flow-like of the marks of the landslide.Secondly,this paper propose the D-P-B coupling constitutive model which combine the D-P solid constitutive and the Binham fluid constitutive by the transformation criterion of the solid-fluid and the M-C-B coupling model which combine the modified Mohr-Coulomb solid constitutive and the Binham fluid constitutive by the transformation criterion of the solid-fluid.Then the simulation result will be compared with the field data and the results of other analytical methods.Analysing the law of movement through the rate of flow-like,and researching the influence of the relevant parameters,for examples: elasticity modulus,cohesion,friction angle and coefficient of viscosity.Finally,through analyse the transformation criterion of the solid-fluid,demonstrating the feasibility and effectiveness of the coupling model.