古贤水利枢纽工程重力坝典型坝段地基渗流分析

Seepage Analysis of Base in Typical Gravity Dam of Guxian Water Conservancy Project

古贤水利枢纽重力坝典型坝段地基地质条件复杂,剪切带发育多且渗透性较强,在上下游高水头差的作用下,具有潜在的渗透破坏,且影响防渗排水系统的渗流控制效应,因此选取了重力坝典型坝段,评价了地基的渗流场分布特征和防渗排水系统的渗流控制效应,对渗控体系进行了优化设计。结果表明,渗流经过防渗帷幕和排水孔的排水降压作用后,地基的孔隙水压显著降低,防渗排水系统的渗控效果显著;排水孔底和穿过剪切带的排水孔附近的渗透坡降相对较大,易发生渗透破坏;副排水孔和辅助排水孔的设置对坝段的单宽渗漏流量影响较大。

The geological conditions of base in the typical gravity dam section of Guxian water conservancy project are complex,and there are many shear bands among the base which are more permeable.Under the effect of high water head between upstream and downstream,there are potentially penetrating damages,which influence the seepage control effect of anti-seepage drainage systems.Therefore,it is necessary to evaluate the distribution characteristics of the seepage field of the base in typical gravity dam section and the seepage control effect of anti-seepage drainage systems in order to optimize the design of seepage control systems.The results show that the pore water pressure of base is significantly reduced after seepage through anti-seepage drainage systems,which have remarkable seepage control effect.The gradient near the bottom of the drain hole and the drain hole passing through the shear bands is relatively large,which is easy to cause penetration damages.The setting of auxiliary drainage hole and auxiliary drainage hole have a greater influence on the singlewidth leakage flow of the dam section.