The Temporal And Spacial Prediction Theoretical Model Of Landslides Catastrophe Process And Its Application

Geologic disasters of slope failure frequently happen in Chongqing area, subsequently great economic and people losses are brought to this area. With the social economy's continuous development, as a typical geologic disaster, landslide's serious harm has deeply affected the local citizen's daily life. Although the temporal and spatial prediction theoretical model of landslides has made great achievements in these years, there are still exist many insufficiency of knowledge on the complex physical properties and nonlinear mechanical characteristics of landslides. So, it is necessary to research on the evolving rule of landslides.This work is supported by the Ministry of Science and Technology of China (No. 2004BA901A02). Three new theoretical models are proposed in this paper, which are three dimensional stability analysis model of landslides with single slip surface, three dimensional stability analysis model of landslides with multiple slip surface and failure time prediction model of landslides. Moreover, the kinetic rule of sliding body and rockfall are also discussed in this thesis. The main conclusions are summarized as follows:â‘ Based on the assumption of the normal stress distribution over the three dimensional slip surface, a new stability analysis model of landslides with single slip surface is established. This new model satisfies all the force and moment equilibrium conditions, in which no iterative calculations are needed. An explicit expression for safety factor, which make it more applicable to the practical engineering, is given out. In addition, On the basis of the upper bound theorem of plasticity, a new slope stability analysis method is proposed in this paper, in which the Mohr-Coulomb associated flow rule is adopted here. The solution formulae of safety factor are obtained, in which the interaction between slip surfaces are taken into account.â‘¡Based on catastrophe theory and monitoring data, a time prediction model of landslide is established, in which the rheological behaviors of medium on sliding surface are taken into account. On the basis of the bifurcation set of cusp catastrophe theory, the formula to predict the sliding time is derived, which can be applied to forecast landslides. Meanwhile, the formulae of initial sliding velocity are obtained by using energy transformation theory.â‘¢A spring-block model to forecast the movement of sliding body is presented, in which the deformation and speed inhomogeneousness of sliding mass, the energy conversion and dissipation and the friction on the slip surface are also considered. The deformation of single sliding body in the whole sliding process can be determined by numerical method. In order to take the effects of the profile on the trajectory of rockfall into account, the boulder is approximately supposed to be elliptic. On the basis of contact mechanics, the expression of restitution coefficient, which the elastic-plastic deformation of earth is considered, is presented in this paper.â‘£Based on the temporal and spacial prediction theoretical model (TSPM V1.0), the numerical software MATLAB is adopted to compile calculating program,. Finally, in order to examine the present theoretical model, the program is applied to the temporal and spacial prediction of Xiangjiashan Landslides. By comparison with traditional methods, the temporal and spacial prediction theoretical model is validated.