Fem Analysis Of Elasto-Plastic Large Deformation On Slope Stability

The stability of slope is one of the important study matters in rock mechanics. At the times, slope problems have become one of the three world calamities apposing earthquake , volcano, namely, the well-known coast, mud which can arouse grave economy loss,e'en casualty. So it is fully available that trying to find out a sort of technique which can analyze slope accurately and lessen coast disaster.Geometric nonlinear FEM can more accurely simulate rock and soil,what's more , can take into account the nonlinear constitutive relation. At the same time ,it can reflect more true deformation and stress distrbution of slope.The updated Lagrangian method of large deformation for the stability analysis of slopes is intrduced; and then the equation of elasto-plastic large deformation FEM for the large deformation of slopes are presented.When the stability of slope is evaluated, Safety factor is given , but all kinds of methods based on rigid body limit equilibrium cant not analyze the breakage process of slope because of their dummy labor state. One the contrary, adoping strength reduction method,i.e, during nonlinear FEM's computing debasing material intensity, can simulate the stability state of slope from strong strength to ebb strenghth of material.,and then make certain the safety factor .In this dissertation ,the principle of this method is discoursed upon. And ANSYS6.1 is applied, adopting Mohhr-Coulomb equivalent area yield criterion.,to analyz the development of displacement field , stress field , plastic section. The results are well coincident with the results calculated by small deformation FEM , limit equlium slip curve(surface)theory.Finally, Fast Lagrange Analysis of Continua(FLAC) is used to analyz the stability of slope. From the results ,it is obvious that error of the safty actor out of FLAC and the elastico-plastic large deformation(EPLD) FEM are both more smaller, moreover, they are close to each other. This is rooted from the single superiorities of FLAC which make the results of FLAC more credibleAt the same time, the calculation resultis of EPLD,which consider not only the nonlinearity of soil material but the geometric nonlinearity in the process of failure stability, are more reasonable.