Research On Stability Evolution Of Reservoir Bank During 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 bank 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. 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, taking Baima bank as example, in accordance with the Three Gorges reservoir scheduling, Applied FLAC3D numerical simulation software to calculate Baima slope stability factor form 175m to 145m and analyse the trend of the stability. Meanwhile, programming Fortran language to calculate the corresponding seep field of Baima Slope. Then combining the results with the Baima slope, and using the traditional method to calculate Baima slope stability factor. Through the comparison of two methods, we draw conclusion that the water level alteration, especially water level drawdown, has a great impact on the stability of Baima slope.In a word, the stable evolution of landslide became a downward trend.Third, slope stability by summarizing the factors that impact analysis found that the evolution of the slope stability trends and changes in water level and the intensity of rock and soil degradation, In accordance with physical parameters experimental data of Baima slope, fitting rock strength degradation formula and combining catastrophe theory Baima Slope Stability evolutionary trends with water changes, which speculates slope failure time. Baima slope, through the rise and fall of water 50 times, is possibly instable. Fourth, slopes of Three Gorges reservoir area can be simplified as line-type slopes, under backwater affected, the starting point of graphic calculation-design low water level position may change. So it is necessary to analyse Graphic determination of the starting point. Then taking Kaqiujin appropriate amendments graphic calculation, considering the wave and the low water level position, and applied amendment method to predict the width of Baima Slope Collapse and comparising with Kaqiujin method in the collapse prediction, which is reasonable, the results of the study can be applied to prediction and prevention of bank collapse.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 Fengjie Baima Slope bank are obviously increased, it is show that the landslide has the obvious response to the storage, the water down will cause the stability of landslide present the reduction tendency.