某水库坝基渗透稳定性研究

Study on seepage stability of a gravity dam foundation

某拟建高为22 m的混凝土重力坝坐落于第四系冰水堆积层之上。在大坝上下游水头差的作用下,产生库水渗漏。库水的大量漏失,不但可能使大坝蓄水达不到设计高程而影响工程效益,而且,水流的渗透作用还会导致地基岩(土)体的恶化,产生渗透破坏,影响大坝本身的安全。在现场调查基础上,用数值模拟方法评价了该水库在库内设置175 m长铺盖条件下的渗漏问题,计算了水库的渗流量、大坝基底的水力坡度。因其量值较大,必须在渗流出口处采取反滤层等工程措施,给相关部门提供设计依据和决策参考。

A concrete gravity dam of 22m height will be constructed on the Quaternary glaciofluvial accumulation layer. The leakage of the reservoir is resulted in the difference of the water head between the upstream and downstream of the dam. A great deal of leakage could cause the reservoir water stage not up to the designed level and then influence the engineering effect. The osmosis from the leakage could cause the depravation and seepage damage of the dam foundation, and influence the safety of the dam. On the basis of field investigation, numerical stimulation method is used to estimate the seepage of the reservoir and calculate hydraulic gradient of the dam base on the condition that a blanket of 175 m length is designed in the reservoir. Because the seepage volume and the hydraulic gradient are very large, many measures such as inverted filter, etc. are suggested to offer the reference for designing and decision.