松塔水电站大坝下游河床库水渗漏出逸问题研究

Discussion of Leakage from the Riverbed at the Downstream of Songta Hydropower Station

松塔水电站为新建工程,拦河大坝为坝高62.6 m的均质土坝,下闸蓄水后下游河床约1 km^10 km范围内出现严重的渗漏出逸。通过对渗漏出逸区的地质勘察及综合分析确定渗漏出逸的主要原因为坝基渗漏及两岸绕渗,同时与大坝修筑前该河段原有的泉水出流通道有直接关系。由于坝址区地质情况比较复杂,在渗漏通道准确定位方面仍存在较大困难,需在设计处理方案的基础上进一步开展地下水渗流动态观测及三维渗流数值模型分析,确定渗漏通道的准确空间位置及特性,以求圆满解决松塔水电站水库渗漏问题。

Songta hydropower station is a brand new project ,its dam across the river is a soil-based foundation with the height of 62 .6 meters .Once the sluice gate was released for impoundment ,there were severe cases of leakage and over-flow in the downstream river beds within the scope of 1 to 10 kilometers .According to the geological survey of the leakage area and comprehensive analysis ,two possible reasons for leakage were proposed ：leakage from the dam base and dam bypass leakage on both sides of the dam ,which were closely related with the fact that before the dam was constructed , there was a problem of original downstream overflow out of channels .Moreover ,because the actual geographical situation was complicated ,it was hard to locate the leakage channels .In order to solve the leakage problem thoroughly ,further dynamic monitoring of groundwater leakage and three-dimensional numerical model analysis should be done in addition to the designed treatment plan ,to determine the accurate leakage location and its characteristics .