As the geological conditions in west China are are complicated, deep overburden foundation often exists in the construction of earth-rock dams. Deep overburden foundation results in the leakage of reservoir and possibly endangers the safety of the dam, so the seepage control problem is particularly prominent and urgent. A water conservancy project in Tibet was taken as an example and finite element analysis method was used to conduct two-dimensional and three-dimensional calculation of infiltration line and seepage quantity and stability of 8 kinds of seepage control schemes of this project, such as"no impervious"/'upstream clay blanket", "downstream mattress drainage", "downstream clay gland", "non-impervious dam foundation", "hanging concrete anti-seepage wall", "down with curtain grouting anti-seepage concrete wall"and"impervious wall". The relationship between optimum anti-seepage scheme selection and seepage coefficient was found out, and the effect of the scheme of deep overburden layer of vertical seepage control was verified, wich may be used as a reference for similar engineering.%我国西部地区地质条件复杂,土石坝建设中经常会遇到深厚覆盖层地基.深厚覆盖层地基的存在,将导致水库渗漏,并可能危及大坝安全,其渗流控制问题显得尤为突出和紧迫.以西藏某水利枢纽工程为例,采用有限元分析的方法,对该工程“无防渗”、“上游黏土铺盖”、“下游褥垫排水”、“下游黏土压盖”及“坝基无防渗”、“悬挂混凝土防渗墙”、“混凝土防渗墙下接帷幕灌浆”、“全防渗墙”等8种防渗方案从渗漏量、浸润线和渗透稳定性等几个方面进行了二维及三维比较计算,得到了最优防渗方案的选取与坝基渗透系数之间的关系,验证了深厚覆盖层坝基垂直防渗方案的明显效果,可供同类工程参考.
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