中文摘要：

卡拉水电站坝址区河谷狭窄,岸坡陡峻,地质条件复杂,渗漏问题突出。为减小卡拉坝区渗漏并改善大坝的渗透稳定性,工程设计采取防渗帷幕、排水孔幕和排水洞等防渗排水措施。采用子结构、变分不等式和自适应罚函数相结合的方法（简称SVA方法）,结合典型溢流坝段与坝区整体渗流场分析成果,评价卡拉大坝及坝基渗流控制方案的合理性,并论证其优化的可能性。研究表明：①防渗帷幕有效雍高了帷幕上游侧岩体内的地下水位、增加了绕坝渗流的渗径长度并降低了坝基的扬压力,排水系统则显著降低了坝体内的孔隙水压力以及坝基扬压力;②排水孔幕间距对坝体内的自由面分布有着显著影响,排水孔幕间距取3.0～4.5 m是合适的。

英文摘要：

The Kala Hydropower Project,located in a narrow and deeply-cut valley on the middle course of the Yalong River,is subjected to serious seepage and leakage problems due to complex geological conditions at the dam site.In order to reduce the quantity of seepage flow through and around the gravity dam and prevent the dam and its foundation from seepage failure,a seepage control system consisting of grouting curtain,drainage hole array and drainage tunnels is designed.For performance assessment and optimization design of the seepage control system,a numerical method combining a substructure technique,a variational inequality formulation of Signorini＇s type and an adaptive penalized Heaviside function（short for SVA method） is adopted.Numerical results at a typical overflow dam section and the whole dam site demonstrate that the primary design is a proper and considerable scheme for seepage control but further optimization can be performed in designing the layout.The results show that： ① the grouting curtain can effectively raise the groundwater level at the upstream of the grouting curtain,increase the bypass seepage path and reduce the uplift pressure in the dam foundation,and the drainage system can significantly reduce the pore water pressure in the dam body and the uplift pressure in the dam foundation;② the drainage hole spacing has significant effects on the free surface locations with an appropriate spacing of 3.0~4.5 m.