Study On The Formation Mechanism And Dynamic Model Of Landslide By Earthquake And Rainfall

Slope landslide usually occurs in a special geological background conditions, due to a large amount of rainfall and earthquake. It involves the field including roads, railways, and water projects. Slope body belongs to the discontinuous medium, and its microcosmic mechanical properties, state of stress and the law of displacement, the contact relationship of microstructure particles, contact number, and sliding ratio with the changes of positions and conditions. Slope numerical simulation was based on the theory of discrete element granular flow, which characteristic has no assumption of material constitutive relation, slip crack surface, continuity equation of displacement and deformation coordinate equation, while directly define the contact relationship among particles, getting stable state natural adjustment process according to the slope internal material itself through the visual on the slope landslide process for dynamic simulation, thus from macro microcosmic to reveal the formation mechanism of the landslide.This paper based on the slope landslide situation of mountainous highways in Fujian province. Firstly, the biaxial test of discrete element numerical method was used for making a simplification microcosmic mechanics model of the slope.Secondly, the saturated soil fluid-structure coupling of micromechanics model was established to simulate rainfall induced landslides process, the formation mechanism of the Rainfall induced landslide was revealed by the analysis of displacement field, stress field and velocity field and microcosmic particle contact number, porosity, sliding ratio of the slope.Following, the typical seismic wave was used to establish wave propagation equivalent relationship in continuous medium and discrete medium, and simulate the dynamic boundary conditions under the action of earthquake. The displacement, velocity, stress distribution of slope internal particles were analyzed during the seismic process.And analyzed the microcosmic structure changes including porosity, contact number, slips ratio. Through the contrast in different slope seismic moment microcosmic fabric change rule of earthquake, explored the formation mechanism of the seismic landslide, and analyzed different factors on the influence of earthquake landslide.Finally, the relationship between time and space of earthquake rainfall and landslide are drew out, select earthquake in the first and then rainfall to research, using a reasonable model, and reach a conclusion that the duration of earthquake rainfall is shorter than rainfall condition by comparing the numerical results with the previous.