Analysis of dramatic bedding landslide on dynamic instability and disaster factors

In order to prevent the geological hazards of bedding landslides along the highway in mountainous areas, it is necessary to scientifically analyze the dynamic instability mechanism and the characteristics of the disaster-causing factors. On the basis of considering the effect of the retaining body, water pressure and compression deformation energy, a generalized chained regressive geomechanical model consisting of a slider, a lying soft rock and a retaining body was proposed, it also analyzed the four evolutionary stages of chained regressive phenomenon which included the initial stage of excavation, the middle stage of fracture development, the middle and late stage of system quasi-static deformation, and the stage of system instability before sliding. The stress field was derived by elastic theory. Based on the principle of energy conservation, the incremental balance equation of the generalized model was established, and the analytical formulas of the energy release curve and the energy dissipation curve, as well as the dynamic landslide starting slip force parameters were obtained. The method was applied to the landslide on national road 319 in Pengshui County, Chongqing city. Results illustrate: the generalized flexibility and generalized displacement are the control parameters for the dramatic instability of the slope. Energy accumulation, energy release curve and energy dissipation curve have two types: no intersection point and double intersection point. No intersection point corresponds to creeping slumping, and double intersection point corresponds to violent slumping. The contribution to the deformation energy accumulation is sorted from largest to smallest, followed by slider compression deformation energy, the function of the retaining body and the water pressure, among which the compression deformation energy of the slider cannot be ignored. The role of the retaining body has the dual effect of preventing sliding and increasing the deformation energy of the slider. The fissure water has a dual effect of hydrostatic pressure and erosion weakening effects. At the same time, the FLAC^3D finite difference method is used to verify the rationality of the theoretical model. The research results further explain the catastrophic law of the downhill chain regression model, reveal the disaster-causing efficiency of each influencing factor, it can provide a certain theoretical basis for the research and development of mountain road slope maintenance and disaster reduction technology.