西藏雅鲁藏布江中游河段电站目前处于加速开发阶段，藏木下游河谷两岸阶地覆盖层厚度较大，范围较广，待开发电站均存在深厚覆盖层的绕坝渗漏及渗透稳定问题，在进行防渗方案设计时，由于覆盖层透水性强，垂直河道的水力坡降较小，其防渗帷幕线难以延长至正常蓄水位线与地下水位搭接处。因此，采用达西定律和三维有限元两种方法对该电站的绕坝渗漏及渗透稳定问题进行分析计算，研究讨论防渗帷幕线的长度及深度，从而确定左岸阶地的防渗型式，以期对西藏地区同类型的水电站建设有借鉴意义。%The power plants at middle reaches of the Yarlung Zangbo river is currently in the accelerating development stage ,it has a large thickness and wide distribution of overburden of terraces on both sides of the valley downstream of Zangmu,all the power plants to be developed present the probloms of around the dam leakage and permeation stability of deep overburden .During impervious design ,since the water permeability of overburden is strong ,the hydraulic gradient which is perpendicular to the river is small ,it is difficult to extend impervious curtain line to the intersection of normal water level and the groundwater table .Therefore ,the authors use two methods of the Darcy ’s law and three dimensional fi-nite elementthe to analyze and calculate the around dam leakage and infiltration stability of the power station ,study and discuss the length and depth of the impervious curtain line ,to determine the seepage prevention type for the left bank ter-races,in order to have reference significance for the construction of hydropower stations in Tibet which has the same type .
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