三溪浦水库防渗墙下游侧水位偏高的成因分析

Cause Analysis of High Water Level at Downstream of Cut-off Wall in Sanxipu Reservoir

为了分析三溪浦水库维修加固工程后混凝土防渗墙下游测点水位实测较设计计算结果相比偏高的原因,在排除混凝土防渗墙施工质量问题的前提下,通过维修加固工程前大坝渗透状态与相关资料分析,发现维修加固工程前坝体及坝基的渗流场的渗透坡降较大,在长期的高坡降作用下心墙内细颗粒被渗透水流带入松散的砂砾石透水坝基内沉积下来,从而将坝基淤堵,抬高了该区域的浸润线,最后利用测点的实测水位反演坝基的渗透系数,获得了与实测值较为相符的大坝渗流场,并发现反演得出的坝基的渗透系数比原设计采用的坝基渗透系数小,而与心墙的渗透系数较为接近,从而初步验证了坝基淤堵这一结论的合理性。

In order to analyze the reason of the high water level of the downstream observation point of the concrete cutoff wall,the seepage state of the dam before the maintenance and reinforcement project along with some other related data was analyzed on the premise of eliminating the construction quality problem of the concrete cutoff wall. It was found that the seepage gradient of the dam foundation is large before the maintenance and reinforcement project. The fine particles in the core wall were deposited by seepage water into the loose sand-gravel pervious dam foundation under the action of long-term high slope gradient,thus the dam foundation was clogged and the saturation line in this area rose. Finally,the seepage coefficient of the dam foundation is calculated by the measured water level of the dam foundation,and the results showed that the permeability coefficients of dam core and foundation are identical which can be a preliminary verification.