Rock Slope Stability Study On Conditions Of Reservoir Water Level Fluctuation

Slope's deformation and destruction is a complex process.Excavation and impound are the common and important factors leading to slope failure.So slope stability study upon excavation unloading and reservoir levels is very important to the slope's excavation engineering and supporting measure.In this paper,numerical simulation is carried out upon the detailed field survey and experiment to evaluate the slope stability in the conditions of excavation in stages and supporting measure.The main conclusions are as following:?1?The reservoir slope of Fukang pumped storage power station has little highly weathered rock and the weakly weathered depth is about 28-80 meters with an average depth of 60 meters.And the lightly weathering depth of slope is 60-80 meters.The weakly disturbed depth of the slope is about 7-40 meters.?2?There is no?-class but two?-class structural surface?F28 and F29?in the project area's.The massiveness of rock mass is poor in most part of slope.In addition,the rock structure is mainly the mosaic structure and sub-block which controlled by fracture spacing.?3?FLAC^3Dnumerical simulation results show that the maximum and minimum principal stress concentrate on the excavation slope base accompanying the process of excavation carried out.And the large displacement values generally appear in the front of excavation face.In addition,the plastic zones distribute alone the bridleways and excavation slope with mainly shear failure and tensile failure accompanied.?4?based on the analysis of fluid-structure problems,enter the calculation cmmand to simulate the active reservoir level,and than combine it with fluid-structure calculation.After the rockfill dam model constructed,the fluid-structure numerical simulation is carried out.And the results show that when the water level rises to the highest level,phreatic line of the slope lags after the water level in reservoir.The principal stress reducing is the main trend after the water level rises and the plastic zone develop quickly.On the other hand,when the water level declines from the highest level,phreatic line's rate of decline of the slope lags after the water level in reservoir and forms a groove-shaped in the slope.The principal stress increasing is the main trend and the displacement is further increased under the pore water pressure which has negative influence on the stability of slope.In the meantime,the plastic zone develops quickly with mainly tensile failure.