Nonlinear Finite Element Analysis Of The Influence Of Landslide Shape On Its Deformation And Instability

A large number of landslide examples indicate that the deformation and instability of accumulation layer landslides are closely related to their own geometric characteristics,and their deformation patterns mainly include two types: sudden instability and gradual instability.Landslide rock and soil are typical nonlinear materials,often accompanied by significant displacement during the deformation process.Analyzing their deformation and instability requires simultaneous consideration of geometric and material nonlinearity.In view of this,based on the theory of large deformation and the basic principles of finite element analysis,this article improves and develops a finite element solution method for large deformation of landslides.The study focuses on the sudden instability type and slowly stabilizing type landslides,and analyzes the deformation and instability laws of the two types of landslides,and conducts a study on the impact of landslide shape on their deformation and instability.The main research work is as follows:(1)Improved and developed the finite element method for landslide deformation and instability considering geometric and material nonlinearity.Aiming at the highly nonlinear problem of large deformation equation of landslide,a numerical method and solution path for large deformation of landslide are developed.Numerical processing techniques such as adaptive step size iteration,optimization of non-zero element data storage,and the solution method of conjugate gradient equation are used to realize the finite Metacomputing of large deformation problem of landslide,and related calculation and analysis programs are compiled.A comparative analysis was conducted using a circular arc arch example,and the numerical solution was in good agreement with the theoretical solution.The reliability and applicability of the calculation program were verified,providing a numerical research tool for future research work.(2)A method for describing the shape of landslides in accumulation layers was proposed.A mathematical model was used to generalize the geometric shape of the slope and sliding surface of the landslide.By fitting the shape of the real landslide,the area,center of gravity,and other characteristic parameters of the model landslide and the real landslide were compared and analyzed.The two were in good agreement,verifying the reliability of the method.(3)Taking the Longtoushan landslide as the research background,the changes in displacement and shear strain during the deformation process of a slowly changing and stabilizing landslide were calculated.The effects of factors such as landslide slope,slope surface morphology,and sliding surface morphology on the deformation and instability of a slowly changing and stabilizing landslide were analyzed.The results indicate that the displacement of the landslide center of gravity and the deformation of various parts increase with the increase of load.When the load reaches a certain level,the deformation tends to stabilize.Under the same load conditions,the steeper the slope of the landslide,the more concave the sliding surface shape,and the more convex the slope surface shape,the greater the displacement and shear strain generated by the landslide body,and the smaller the critical load of the landslide.(4)Taking the Lannihu landslide as the research background,the deformation laws of sudden unstable landslides were analyzed,and the effects of factors such as landslide slope,slope morphology,and sliding surface morphology on the deformation and instability of sudden unstable landslides were studied.The results indicate that with the increase of load,the deformation and deformation rate of the landslide gradually increase,and the cumulative displacement of the landslide decreases with the increase of depth.Under the same load conditions,the steeper the slope of a landslide,the smaller the displacement of its center of gravity,the greater the maximum shear strain,and the smaller the critical load.The more concave the sliding surface of a landslide is,the more convex the slope surface is,the greater its center of gravity displacement and maximum shear strain,and the weaker the bearing capacity of the landslide...