Research On Strength Reduction Technique For Earth-rockfill Dam Dynamic Stability Analysis

With the high development of computer technology, as a slope stability method, strength reduction attracts more and more engineers' attention. This method has many advantages. Such as it has a explicit conception, a visual physical model, parameters that are easily acquired, needless shape of slope critical assumption and it is fitted to complicated boundary. Most of all it can get a safety factor that is highly close to the safety factor of traditional limit equilibrium method. So the method of strength reduction is being researched and applied step by step. However, the application of this method to slope stabilization with the effect of dynamical earthquake still hasn't been worked over further.On the basis of analyzing slope stabilization under the action of gravity, this paper applies strength reduction method to analyzing slope stabilization under the earthquake. First, through 3-D nonlinear finite element analysis, initial stresses are got. Then through dynamical analysis, every instantaneous acceleration distributing of slope under dynamical earthquake can be got too. According to this result, adding earthquake force to structure by way of inertial force, this paper analyses the slope stabilization by using FEM strength reduction method and gains every instantaneous safety factor and its corresponding slide. Curves of safety factors versus duration can be made by curvefitting. By safety factors versus duration curves and slides, we can value structure's quakeproof stabilization and point its slide out. By these principles, programs of FEM stabilization analysis for each moment are organized. Some examples analyzed by this method validate the rationality of applying FEM strength reduction to slope stabilization analysis under the action of dynamical earthquake.At last, this paper uses this method to analyze the static and dynamical stabilization of Nuozhadu Dam. A safety factor and a critical slide of each case are educed. Compared with the result of the limit equilibrium method and FEM searching method, conclusions can be made that FEM strength reduction method is reasonable and applicable in practice and design of Nuozhadu rubble Dam is reasonable.