恰让水库坝基渗漏量模拟和影响因素分析

Quantity calculation and influence factor analysis of seepage in Qiarang Reservoir dam

水库坝基的渗漏问题一直是影响水库大坝稳定性的主要问题之一,因此确定渗漏位置与计算渗漏量尤其重要。本文以恰让水库为例,采用数值方法计算了坝基的地下水位和渗漏量,并与实测水位和渗漏量进行拟合,反演得到坝基岩体和断层的渗透系数。基于反演的渗透系数,考虑了增加帷幕深度、部分断层灌浆以减少渗透系数的方法,对坝基渗漏量进行了预测。计算结果表明,左岸渗漏量约占总渗漏量的40%,而右岸为60%,因此大坝右岸为主要渗漏量来源,其中通过F2断层和F17断层的渗漏量约占总渗漏量的26%和11%,因此这两条断层为坝基处主要的渗流通道。水库蓄水位的大小、帷幕的渗透性以及断层的存在都对坝基的渗漏量有影响,其中顺河向断层的影响较大。

Seepage beneath the reservoir dam is one of the major problems affecting dam stability. It is very important to locate the leakage and predict the amount. Taking Qiarang Reservoir as an example, the groundwater level and seepage amount is estimated with numerical method, and then fitted with the observation data, the permeability of fault and bedrock mass is derived by reverse calculation. The dam seepage amount is forecasted after increasing the grout cut-off depth and grouting in the fault. The calculation results show that the left bank leakage is about 40% of the total leakage, and the right is 60% , the right bank is the main source of leakage, the leakage from the main seepage channel, faults F2 and F17 is 26% and 11% respectively. The dam seepage is affected by the reservoir water level, grout cut-off permeability and the faults, among which the fault inclined to the river is the major factor.