Three-dimensional Finite Element Optimization Analysis of Different Seepage Control Schemes of Lizhou RCC Arch Dam

The seepage control measures were investigated for the dam area of Lizhou hydroelectric project in Muli River of Sichuan Province.A three-dimensional finite element seepage model was developed using ANSYS12.1 to analyze the seepage characteristics and variations of seepage pressure under different seepage control schemes.The seepage gradient and seepage amount of key positions and the seepage pressure and groundwater level of typical profiles of seepage field for different seepage control schemes were compared.The results showed that(1) the impervious curtain and drainage hole in the design scheme of seepage control measures of Lizhou arch dam can decrease the seepage saturation line effectively,lower the uplift pressure on dam foundation and dam abutment,and improve the stress conditions of dam foundation and dam abutment;(2) the deepening curtain,drainage hole,and thickening curtain have insignificant effects on decreasing the seepage pressure;and(3) increasing the depth of impervious curtain near the f5 fault can prevent the formation of leakage passage in the f5 fault.In addition,removing the drainage hole in the first layer and decreasing the extending length of the impervious curtain of dam abutment can save the cost of seepage control measures without breaking seepage safety.