深厚覆盖层上土石坝的渗流控制方案研究

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。

Research on seepage control schemes of earth-rock dam with deep overburden layer

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.