Stability Of Slope Under Rainfall And Large Group Decision-making Study On Landslide Treatment

For unsaturated soil slope the rain infiltration is one of the most important factors that can result in landslide. The saturated-unsaturated seepage theory, rainfall infiltration theory and the unsaturated soil shear strength theory are used to conduct stability analysis of the slope under different rainfall situations. The large group decision-making method about the option of slope treatment is discussed. The main conclusions are as follows:1. The saturated-unsaturated seepage theory under rainfall condition and the governing equation of unsaturated seepage are introduced. The boundary conditions are attained. The FEM format of saturated-unsaturated seepage differential equation is derived from Galerkin's weighted residual approach. SEEP/W flow calculation procedures are adopted to analyze the effects of seepage field with variation of rainfall intensity, duration of rainfall, and soil permeability coefficient, and get numerical solution of 2-dimension hydrological field in the slope.2. The unsaturated soil shear strength theory is introduced. Since rainfall seepage is regarded as an important factor in soil slope stability analysis, the distribution of pore water pressure of seepage field is calculated and introduced into the formula of factor safety using SLOPE/W module software.3. Since slope treatment decision-making belongs to multi-attribute group decision-making problems, a multi-scheme large group decision-making method based on multi-attribute characteristics is proposed. In the method model and algorithm of single scheme large group preference is expanded into multi-scheme one to obtain the large group preference matrix firstly. Then, the ordering weights of every scheme are obtained by using the entropy weight method. The integrative evaluating value vectors of all schemes can be obtained by using the ordering weights and the large group preference matrix. Finally, the integrative ordering results for all the schemes are obtained through the integrative evaluating value in the vector. A case study is given to illustrate the effectiveness of the method.In this paper, unsaturated soil slope stability analysis under various seepage situations is fully performed, and the multi-attribute multi-scheme large group decision-making method about the option of slope treatment is proposed and applied to a case study.