Study On Stability Of The Reservoir Bank Slope On The Condition Of Reservoir Water Level Fluctuation

A large number of failures of the rock engineering are related to the underground waterand the rock slope has inseparable relationship with it. Accoring to statistics that90%of theslope failure is caused by direct or indirect effects of the underground water. In consequence,it is very important to take the effect of the hydro-mechanical coupling into account whileevaluating the stability of the rock slope. The paper summarizes the features and thecomputing models of the hydro-mechanical coupling. Taking the slope of Zhen’an pumpedstorage power station as an example, we discussed the equivalent continuum model.Furthermore, we analyze the characteristics of the stress field and the stability of the slopeinfluenced by reservoir water level fluctuation.The main conclusions of this paper are as follows:（1）The paper presents the features of hydro-mechanical coupling which includes thephysical model of hydro-mechanical coupling and the relationship between permeabilitycoefficient and stress.（2）The math models of hydro-mechanical coupling is summarized including theequivalent continuum model, the fracture network model and the double-medium model. Thecalculation methods of the hydro-mechanical coupling include the finite element method anddiscrete element method. The two methods have their own advantages and limitations.（3）Taking the slope of Zhen’an pumped storage power station as an example, the paperstudies the engineering geological conditions and estimates the shear strength parameters byHoek-Brown criterion. The result lays the foundation for the slope stability analysis.（4）The paper builds the equivalent continuum model, and studies the characteristics ofthe stress field influenced by reservoir water level fluctuation. According to the result of thesimulation, the paper summarizes four results as follows:1、The permeability of the rock haslarge influence on the seepage. The changing shape of the stream line becomes obvious on theline between different permeabilities. With the groundwater lever rising, the downstreamslope overflows.2、The seepage has little influence on the maximum and minimum principalstress. But the monitoring sites of the slope are significantly affected by it. Seepage influencesthe shear stress by the effective stress.3、 The seepage has no influence on the location of theslope failure. It changes the displacement of the slope.4、With the reservoir water levelincreasing, the stability coefficient decreases, on the contrary, the decrease of reservoir waterlevel leads to the increase of the stability coefficient.