| Landslides are serious unstable phenomenon of natural rock mass, and those caused by rainfall is defined as rainfall-induced landslides. Although the causation of landslides of cause includes the inter conditions, such as unfavorable geology, the structure of rock mass and so on, for the other hand, the impact of outside forces are also besides in it. There are quantities of outside forces that can lead to landslide, but undoubtly, among those factors, rainfall especially intensive rain or heavy rain is one of the most important factors. It triggers off landslides, which can be mainly described as below: during the rain, the surface water immerged into the rock mass, which increases the weight of the slope and the pore-water pressure. As a result, the slope turns into the limiting state of equilibrium, and begins to slide. With the rainwater keeps immerging, it breaks into the underground and converts into groundwater, which will emolliate the slope surface and decreases the shearing strength of it. Provided the hypsography and the geology necessary, rainfall will play a vital role in the factors that leads to landslides, as shown in a study. Many experts have made many effective explorations to the relationship between rainfall and landslide both here and abroad. They take different kinds of methods or models to find out the critical value of the raininess or the duration of the rain when landslides took place. With these work, they explain the relationship between rainfall and landslide to some degree, discuss the effects on the slope caused by rainfall from different angles, which laid a better groundwork for the further study of rainfall-induced landslides. Based on the returns of the predecessors, this text collects perennial historical data of the landslides and the rainfall in certain regions. By applying lots of theories, such as system approach, quantification theory, filtration theory and numerical analysis method, the text makes a deep research at many aspects of rainfall-induced landslides, including the feature, the process and the process control, the estimation of stability and the treatment effects of it. The mainly returns are as following:(1) Systematically analyzed the type, the spatial and the time distribution characteristic of rainfall-induced landslides. Then took the rainfall-induced landslides of Hubei Province as the research target; with concentrating on the space and time distribution characteristic of rainfall-induced landslides and the rainfall-factors that closely connected to it, it promulgated some relational rules between them.(2) Analyzed the way that underseepage, rainfall infiltration and the rainfall-factors (includes rainfall, rainfall intensity, rainfall duration, and rainfall pattern) influenced the salability of the landslides.(3) Analyzed the basic concepts, fundamental theories, fundamental equations, and delimitation conditions of the influent fields systematically. Inferred the fundamental formulas and the implementation step of the influent elements in the analysis of the stability of the rainfall landslides, which would provide the basis theory for the further analysis of the influent problems in rainfall-landslides.(4) Established a dynamic model for rainfall-induced landslides based on Lagrange finite element method, and Voellmy rheology was adopted. A practical case of a rainfall-induced landslide was analyzed. Through reproducing the dynamic runout process caused by the landslide, we get a simulated computation result, which fits the actual result well.(5) Introduced a method for computing the stability of the landslides that had been considered the influence of pore-water or rainfall. Combined with the non-saturated shearing strength formula, we made some improvements to the traditional limiting state of equilibrium analytic method, that is to say: the pore-water pressure is imported to the stability computation based on the non-saturated soil theory. In this way, we can get the formula used to compute the stability factor. And we had made a detail description with an example.(6) Based on the fuzzy mathematics theory, and not only considering the influence factors needed in the fuzzy appraisal model of the stability of the convention landslide, but also the rainfall-factors (includes rainfall, rainfall intensity, rainfall duration, and rainfall pattern), we established a fuzzy synthesis appraisal method for computing the stability of rainfall-induced landslides, and some examples are taken to describe the application of it.(7) According to the sudden characteristic of the destruction of rainfall-induce landslides, we established a cusp catastrophe model based on catastrophe theory. With this model, we computed the water content when the slope slides, according to the relationship between water content and rock mass. Then we made a conjecture and a forecast for the destruction according to the impaction on the unit weight, the cohesive force and the inner friction angle caused by rainfall.(8) Directed against the assessment slope treatment schemes being a problem of group decision making, a two-dimension leg-mark selected location method of group decision making of slope treatment is presented. In this method, the simple two-dimension leg-mark coordinate figure or assessment function is used, and the optimal scheme of the decision of slope treatment can be determined. The method is applied to the decision of Erzhong landslide treatment, and its application is discussed in detail.(9) The treatment engineering of landslide hazard is a complex systems engineering. The selection of its treatment schemes is depended on many factors such as technology, economics, environment, and risk. Policymakers have preference information on alternatives, and the attribute weight information is incomplete. To cope with such decision-making question with incomplete and preference information, a similarity degree-based method for triangular fuzzy number multi-attribute with preference information on alternatives is proposed. By using the method, a linear programming model is established firstly, and the attribute weights are derived by solving this model, then, based on a possibility degree formula for comparing two triangular fuzzy numbers and a formula for priorities of complementary judgment matrix, a priority method for alternatives is presented. Finally, the method is applied to the decision-making of Zhafangping landslide in the Three Gorge reservoir area, and a good result is gained, which show that the method is feasible and effective.(10) It had established elastic-plastic finite element matrix of effect analysis of treatment of rainfall-induced landslides of Xigoukou by using the treatment of rainfall-induced landslides of Xigoukou as the vestigated subject, and numerical simulated all operating modes of the course of it, the outcome was the equivalent plasticity strain distribution diagram, sheafing stress distribution diagram, and displacement pharos distribution diagram and stability coefficients of the course of the treatment in all operating modes. The calculation results showed that:â‘ After the treatments, the stability factor of Xigoukou slope was as high as 1.32 in the nature state, which is adherence to the specification; and in the most disadvantage situation (nature state+rainstorm+earthquake), the stability facto also came to 1.11, and this was acceptable according to the safe class.â‘¡After treatment, the plastic zone, shearing stress and the range ability of displacement was greatly improved. Therefore, the effect of the treatment was remarkable, and the government plan meets the stable security requirements well.
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