| With the activity increase and the scale extension of human projects, the engineering landslide is standing out more and more. Especially stepping into 1990's, with the rapid development of irrigation works, hydroelectric power, mine, railway, road, and city construction projects in China, landslide hazard is increasingly serious. People attach more importance to the study of landslide.Wushan County, situated at the middle of three-gorge reservoir, is a important city to be emigrated and reconstructed in the three-gorge project. As a result of complicated geology environment, many geology hazards frequently happen such as landslide in Wushan County. Furthermore, Sidaogou landslide is one of the most important landslides that are relevant to the stability of Wushan new county. Sidaogou landslide situated at the north of Yangtze River and the southwest of Wushan new county, whether the landslide is steady or not relates to the reliability of bank reconstruction, dock building, roadbed along Yangtze and the safety of the life and estate in the landslide area. General engineering geology study on the landslide is of very importance, thus in this dissertation the stability and prevention measure of this landslide have been chosen as the research topic by the author.In this dissertation, area geology background, engineering geology condition and mechanism of deformation-destruction of the landslide are adequately analyzed, and finite element method is applied to analyzing the landslide stability in the study area, then changes of stress field, displacement field, plasticity destruction zone and stability coefficient contour are discussed. On account of natural identity complexity of rocks and soils, density, cohesion, friction angle, slope angle, hole pressure ratio in describing physics and mechanics property of rocks and soils are singly uncertain, so the fuzzy optimization neural networks theory is applied to analyzing the landslide stability in order to probe into a new method of slope stability analysis. On the basis of evaluation of landslide stability in two methods, the prevention measures of the landslide are brought forward according to push force method.The main results and conclusions are as following in this research:(1) The less stability section of Sidaogou landslide is mainly middle-below of slope, when the three-gorge reservoir is sluiced, some of slope(mainly middle-below of slope) will be aroused to slide and lose stability wholly under disadvantage of reservoir water marinating and saturation stress. If the middle-below slope loses stability, the above slope will produce stress looseness and regulation, and bring slope deformation to top extending. It loses stability in tractive slippage model.(2) Calculation of landslide stability indicates that landslide stability is worse and worse if reservoir is sluiced and water level is going up, and the worst condition will happen when thewater level drops from 175m to 145m and six degree earthquake overlaps.(3) Sidaogou landslide is stable wholly in natural state now. When the three-gorge reservoir is sluiced, the underground water level will ascend obviously and mechanics parameters of the slip strip below the reservoir water level can drop further, Sidaogou landslide can lose stability wholly in controlled condition influenced by buoyancy of underground water and saturation stress at water level dropping. The most residual slide force of unit width is 9020kN/m (III-III section) when stability coefficient is 1.15.(4) As a result of complexity of slope stability influence, the evaluation system of slope stability based on fuzzy optimization neural networks theory has been exploited, which has strong specialty and practicability. The object-oriented program method is adopted in system realization. Its merits are objective, visual and mutual, its interface is friendly, process is clear, and easy to use and develop. Adopting this system to evaluate and analyze Sidaogou landslide, the conclusion is consistent with the one of finite ele...
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