Abstract: By analysis on the seepage performance at foundation of some dams which have been in operation for more than 30 years, conclusion was gotten that most dams were of good seepage control effect, seepage reduced as time passing and the requirement of standards on uplift pressure could be met. Some factors would exert adverse influence on seepage control and its durability, such as no proper seepage control measures designed, no intact curtain, defects caused by foundation excavation, grouting disturbed by underground flowing water and et al. Further, some advices were presented, including periodic analysis on the foundation sludge, research on sulfate erosion and timely dredging of drainage holes and reinforcement grouting.

摘要： 20多座已运行30年以上大坝的坝基渗流性态分析表明，大多数大坝坝基渗控效果和耐久性较好，坝基渗漏量逐渐减小并趋于稳定，坝基扬压力满足或基本满足设计要求。设计时未能合理采用渗控措施，施工中没有形成完整帷幕，坝基开挖遗留下重大缺陷，以及帷幕灌浆遭遇地下动水干扰，是影响渗控效果和耐久性的一些重要因素。运行中需定期开展坝基析出物分析，继续对硫酸盐的侵蚀危害机理进行深入研究，及时疏通排水孔和对帷幕进行补强灌浆处理。