Research On The Stability Of High Slope Of The Intake Of Xiangjiaba Hydropower Station

Taking the stability of the high slope of the intake of Xiangjiaba hydropower station as research target, the limit equilibrium method and 3D Elasto-viscoplastic finite element method as research measure, this paper analyzes and appraises the stability of the high slope under different work conditions. The result proofed the design scheme, construction scheme and anchorage scheme. The main study contents as follows:(1) Analyze the stability of the high side slope of intake by Sarma method. In this course, some adverse influencing factors as slope excavation, joint fissure caused by blasting, prolonged storm rainfall and rapid drawdown have been considered. Then, based on the shape of slope and distribution characteristics of joints, study the local stability.(2) Using 3D FEM, three dimensional finite element model of the high slope is presented in this study, analyze the global 3D stress and deformation distribution, considers the effects of excavation, anchoring and different work conditions. Evaluate the stability of the slope, based on the stress and deformation result.(3) Analyze the influence to the stability of the slope that caused by excavation for seepage tunnel and underground power plant.Evaluate the influence to the stability of the slope caused by counter-inclined structure.(4) In order to improve the stability of the slope and ensure the safety in the engineering construction and operation, Some proposals on engineering measures been presented.Studies show that the high side slope of the intake of Xiangjiaba hydropower station will be stable in integer under possible work conditions. But the slope maybe crippling in period of construction and operation because of the cutting by tow clusters joints. In the process of excavation and anchoring: there is not oversize tension stress and plastic zone in rock mass of the slope, the obvious off-load depth is about 3 to 8 meters. The results indicate that the slope can hold stability in excavation period, the design scheme and sequence of excavation and anchoring are rational.The slope of intake will be bolted by systematic bolts. By the calculation, we can get conclusions as follows: the max tension stress on bolts is 54.61MPa, and the max shearing stress is 30.02MPa; the off-load deformation can be control effectively if anchoring istimely; the more deformation which present in local slope rock-mass will make further use of bolts.Excavation for seepage tunnel and underground power plant take some harmful effect to the slope, but it will not damage the slope's integral stability. Counter-inclined structure is propitious to slope holding stability. The slope of intake still hold stability after the mechanical parameter be diminished drastically.