Study On Stability Evolution Of The Large-Scale Bank Landslides Under The Running Of The Three Gorges Reservoir

After the running of the Three Gorges Reservoir, the water level of the reservoir will periodic fluctuate in the range of 145m to 175m every year. Water level fluctuation will soften the rock and soil on the bank, induce the underground water fluctuated and decrease the shear strength, which will influence the landslide stability, and will have the possibility to cause the stable slope to occur landslide. The studies about landslide stability and the evolution in running process of reservoir have become an important topic. At present, the landslide stability evolution in running process of reservoir have not reach a unified understanding, the studies and the actual projects exist the problem of completely dependent on the numerical simulation software or experience, which cause the subjective ingredient in each achievement is rather great. Based on summarize the predecessor research results, by the research technique of unifying theoretical analysis, numerical simulation and example analysis studied this question, the mainly study content and achievement are as follows:First, based on analyze the Three Gorges Reservoir Region landslide engineering geology, summarized the reservoir region landslide distribution characteristic and the large-scale landslide distribution range from the geological structure, the lithologic association, the bank slope structure, spatio-temporal distribution, the climatic change and the coastal section distributes.Second, through numerical simulation ascertain the landslide seepage field under the water level change conditions, then uses the traditional transfer coefficient method to carry on the stable computation, discovered that the stable evolution of landslide has the close relationship with the slope surface configuration.Third, by summary and analysis the factors which influence landslide stability, discovered that the landside stability evolution could divide into drop model and drop–rise model, which take the ratio of water level change speed, infiltration coefficient, specific yield as criterion.Take the Wushan Taping extra large-scale landslide as a example, according to the Three Gorges Reservoir's storage running plan, applies the FLAC3D numerical simulation software, ascertain the ground water seepage field of the landside in reservoir operation process, then used the transfer coefficient method to study the stability evolution. The study shows that Taping landslide is influenced by the Three Gorges Reservoir running, the stability evolution is present the drop model.By comparing the landslide displacement and the shearing strain increment under different water level condition, discovered that along with the rising water level, the displacement and the shearing strain increment of Taping landslide are obviously increased, it is show that the landslide has the obvious response to the storage, the water rise cause the stability of landslide present the reduction tendency.