Study On Slope Sliding And Formation Process Of Landslide Dams Based On Combined Finite-discrete Element Method

The stability and failure of slope has been the key research in geotechnical engineering.The failure process of slope in practical engineering is difficult to realize through physical experiments,while numerical simulation can reproduce the whole process of slope collapse to some degree,and it is easy to study its failure mechanism.The combined finite-discrete element method is the main way to study the failure of slope stability at home and abroad.The rock is discretized into none thickness elements based on a double linear cohesion model and solid element,and the crack initiation and propagation is simulated by the invalidation of cohesive elements,and the solid elements only bear elastic deformation.The Mohr-coulomb model with tensile cut-off is employed as the damage initiation criterion of cohesive element,and the Benzeggagh-kenane based on linear softening is employed as the crack propagation criterion.The study on the accumulation configuration after slope collapse can provide technical reference for slope support.In this paper,the failure process of two slopes are simulated based on the combined finite-discrete element method and the influence of the mesh size on the process of slope movement,the accumulation form and the final moving distance are studied.According to the comparison of final accumulation configuration between the results of simulation and the field observation and other methods,the runout distance becomes shorter as the mesh size becomes larger when the drop phase is same.The results also show that the finer meshes of the FEDM model are the simulation result is closer to the actual effect.Meanwhile,the failure mechanism of the slope is revealed,and the FDEM can be applied to the study of slope damage.The stability of the high slope on the right side of the Red Rock is analyzed in 2 kinds of seismic conditions based on FDEM analysis method combined with dynamic explicit calculation method,The three-dimensional calculation shows that the right bank slope loses its stability along the weak weathering line under working condition 2.The study on the forming mechanism of landslide dam has become a key research subject of many experts and scholars after the occurring of Wenchuan earthquake.The instability process of the landslide is simulated by using finite-discrete element method combined with dynamic explicit calculation method.The necessary rock parameters are calibrated by using numerical experiments of biaxial compression corresponding to the physico-mechanical parameters.The 3D finite model is established by concluding landslide and valley,smaller grid density being applied to the landslide part.And zero-thickness interface elements are inserted into elastic finite elements.The 3D numerical simulation results show that the mechanical principle of barrier dams can be described as follows:the interior damage and deformation accumulation of rock masses are induced by earthquake.Finally,the river is blocked with density,forming the landslide dam.The final formed accumulation configuration of landslide is close to the field situation.