Study On The Three-Dimensional Limit Equilibrium Of Slope Stability

The two-dimensional limit equilibrium tends to be mature, but the problem of the slope transformation and destruction is three-dimensional problem, so, it always estimates the stability and provides the design parameters on the high side through the analysis of two-dimensional model. Since the unknown forces between the slices of three-dimensional slope become more than the two-dimensional, it should be to do more assumptions to solve the problem. Up to now, there are not any effective assumptions to be acknowledged and not any slice methods to be accepted.On the basis of the former studies, this paper studies the three-dimensional limit equilibrium methods and does some works as follow:(1) Puts forward a common model based on the whole force equilibrium through the force equilibrium along a random special line and a common model based on the whole moment equilibrium through the moment equilibrium around a random special line. Through these two models, the former three-dimensional equilibrium methods all can be concluded by two dual integral equations, the problem of the boundary and the slice member also can be avoided, and the computation precision is improved.(2) Develops the three-dimensional Sarma limit equilibrium method, which was built from the two-dimensional Sarma limit equilibrium method by our project team at 2003, and makes the computation result more accordant to the actual condition through relating the direction of the shear force on the slice bottom with the incline of the slice bottom.(3) Builds the common algorithms of the parameter inversion and the residual sliding force of three-dimensional slope, and put them into actual use. At the same time, a new idea for getting the resultant of the residual force is provided.(4) Discusses the infection of the back shearing dot B, the front shearing dot A, the t and the transverse radius Rb to the stability factor of three-dimensional slope, and finds that there are all minimums along with the variety of the B, A and t, except Rb. The computation result shows that the critical potential sliding surface of the three-dimensional slope on the basis of limit equilibrium doesn't exist. So, this paper provides a new idea to get the approximate potential sliding surface through taking the inflexion of the curve between transverse radius Rb and the stability factor. And then, the aptitude optimization algorithms also are used in the optimizing of the three parameters.(5) For the sliding slope, this paper adopt the idea of spatial interpolation and the least squares procedure to fit the floor and the sliding surface (stratum), gets the data for the stability analysis, and make the visualization into use for the three-dimensional slope through the technique of OPENGL.(6) Analyzes the effect of all above methods in the actual engineering through a sliding slope example and a slope example.