深覆盖层上面板堆石坝渗流与防渗墙变形特性研究

Study on Seepage of CFRD on Thick Overburden and Deformation Characteristic of Anti-seepage Wall

斜卡面板堆石坝最大坝高110 m,坝基覆盖层深厚(45～108 m),基岩结构松散,渗透性较强。采用有限元法,对斜卡面板堆石坝及坝基进行了三维渗流及应力应变计算分析,讨论了帷幕厚度、深度与渗透系数对坝基渗流场的影响,分析了防渗墙在施工蓄水过程中的变形趋势以及趾板的沉降规律。结果表明,帷幕是防渗的薄弱环节,帷幕渗透系数增大与深度减小会使总流量显著增加;增大帷幕厚度可较大程度减小渗流量。防渗墙竣工期向上游变位,蓄水期受水推力作用向下游变形。防渗墙与连接板接合部位发生错动,但量值不大。

Xieka concrete-face rockfill dam （CFRD） is of 110 meters height, with an overburden of 45m to 108m on dam foundation. Its bedrock is in loose structure and with high permeability. The three-dimensional seepage and stress-strain of Xieka CFRD is analyzed by using of finite element method. Meanwhile, a discussion is made on the influences of curtain thickness, depth and permeability on dam foundation seepage, and an analysis is made on the deformation trend of the .anti-seepage wall and the settlement law of toeboard in construction and storage periods. The results show that the curtain is a weak link in seepage control. With the increase of curtain permeability and the decrease of curtain depth, the total seepage increases significantly, that is to say, the seep- age can be greatly reduced by increasing the curtain thickness. The anti-seepage wall moves upstream in con- struction period, while it moves downstream by hydraulic thrust in storage period, hence, a small dislocation oc- curs at the junction＇of anti-seepage wall and toeboard.