Research On The Stability Of Dam Slope Based On Shear Strength Reduction

In this thesis, the stability analysis of the dam slope has been studied by finite element method (FEM) with shear strength reduction technique. In this research, the modified Drucker-Prager elasto-plasticity constitutive model has been adopted, which model could consider the different shear strength of soil under different Lode's angle . In some case study, it is shown that the displacement of the dam slope will be increasing rapidly when the shear strength reduction factor reaches a certain value. So a new integrate criterion has been proposed, which includes a horizontal displacement criterion and an angle criterion, and it is vector criterion. Using the criterion, the determination of slope failure state becomes reasonable, simple and visual.Taking a homogeneous soil slope as example, the stability has been studied using FEM with the strength reduction technique, in which the modified Drucker-Prager elasto-plasticity model has been adopted as soil constitutive model, and the integrate displacement criterion was taken failure criterion. The results show that the safety factor and the failure surface by shear strength reduction method is fairly close to the result of traditional limit equilibrium method. So the integrate displacement criterion is reasonable and effectual. The sensitivity analysis of soil parameter has been conducted, the calculation result shows that except the yield criterions, cohesive force and frictional angle, the dilation angle and the density mesh of the FEM is also the influencing factors on the safety factor.Finally, the shear strength reduction technique is used to analyze the seismic stability of Nuo Zhadu core wall type rockfill Dam and Chang Heba core wall type rockfill Dam in FEM.