Stability Analysis Of Reservoir Bank Slope

During the period of construction and operation of large hydropower stations,major landslides and other geological disasters often occur.The change of water level in reservoir area during storage and discharge has become the dominant factor of landslide.How to correctly evaluate the stability of the bank slope under the change of the water level in the reservoir area,and which is prediction and prevention of the slope slip are of important guidance.Based on the investigation of engineering geology,the paper studies the stability of bank slope under the change of water level in reservoir area.The main research contents and achievements are as follows:(1)Through the analysis of permeability height lag phenomenon,considering the error of hysteresis phenomenon,a hypothesis of hysteresis height is put forward,a mathematical equation set is established,and a formula for calculating wetting line is derived.The ideal seepage model of bank slope is established,and the influence rule of seepage coefficient and water drop rate on the stability of the slope is analyzed.(2)Refraction occurs at the interface of soil layers when the seepage of different soil slopes occurs.According to the seepage refraction principle,the dynamic hydraulic calculation method of each layer of soil is put forward,and the stability formula of the slope is calculated by the transfer coefficient method.Take the single block into consideration,the influence of seepage coefficient and interface obliquity on hydraulic performance is analyzed.And the hydrodynamic force is greatly influenced by the refraction of seepage,in which the normal force of the sliding surface changes several times,and the maximum difference of the gliding force is 2~3 times.(3)This paper uses the calculation formula of slope stability to analyze the bank slope relying on the project.When the reservoir water level drops to different heights,the potential sliding bodies on the soil interface can keep relatively stable.The most dangerous sliding surface at the surface accumulation body.After considering the refraction of seepage,the overall slope stability coefficient changes in the range of 0.1.(4)Geo-studio software is used to analyze the stability of bank slope under different working conditions.When the water level is in the initial state and under the selected working condition,the potential sliding surface on the interface of each soil layer of the slope is kept stable.When the water level changes up and down,the most dangerous slip surface method is used to automatically search the bank slope.During the rise of water level,the bank slope remains stable,and during the decline,some of the soil on the surface accumulation layer is unstable and destroyed.