The Analysis And Evaluation Of Treatment Project Effect For Nianshengken Accumulation Body At LiYuan Hydropower Station

LiYuan hydropower station locate in LiJiang city of YunNan province, which programs three cascade hydropower station in eight.Nianshengken accumulation body locate in wide and gradual valley on right bank of dam,the altitude of which spread from 1500 meter to 1700 meter.In the original state the accumulation body keep basically stable, but it start to deform and accelerate the deformation with influence of rainfall and construction. From 2009 to 2011, according to overall treatment plan the phase Ⅰ and Ⅱ projects symbolizes were completed progressively,By comprehensive project management measures we can perform numerical simulation in Nianshengken accumulation body, which we can make research systematically about space defonnation sliding mechanism deeply and make careful analysis and research in all kinds of special state after diversion tunnel operate and reservoir start to conserve water. In the same time it is important to provide scientific help which can deepen and optimize accumulation body treatment plan and make sure the safe of projects or similar projects.Upon making conclusion previous survey data and research result, the paper made double check locally on geological and structural characteristics, and made analysis cause of formation, deformation failure mechanism, and adds the physical mechanical parameters of rock mass from experiments,According to the latest terrain of accumulation body, the three-dimensional numerical model and make full use of FLAC3D to make simulation analysis on stability of Nianshengken accumulation body in Li Yuan hydropower station after before and after treatment projects was completed. And with various stages of monitoring data we can scientifically and reasonably evaluate the result of project, and make simulation and forecast analysis after follow-up project stages. With monitoring data we can make effect assess on treatment plan.By analysis we can get following conclusions:(1) as the physical structure of accumulation body is loose, and shear strength is low. In the original terrain state the accumulation body is stable, but safety coefficient is small. (2) with the influence of rainfall, up of underground water, excavation in open in entrance of diversion tunnel and pile of dross, the accumulation body start to deform and accelerate to develop, which threat safety of later construction and hydropower station operating. (3) the effect of the phase I and II projects symbolizes is fine, which lip of the accumulation body keeps stable and the top half keeps basically stable state of slow creep slippery extrusion. The defonnation has been under efficient control. (4) with the phase III projects symbolizes gradually completed, the treatment plan temporary was completed and it kept stable. By related simulation calculation, it’s predicted that under the all kinds of designed states and special states after the next stage of diversion tunnel operating and follow-up normal water storage reservoir the accumulation body will still keep basically stable.