四川某水库成库条件分析

Analysis of a reservoir forming conditions in Sichuan Province

某水库位于四川盆地西南边缘,长江上游岷江、大渡河、金沙江之间的三角地带,是解决区域灌溉和乡镇供水的中型水源工程。在对水库进行岩溶水文地质调查、地质测绘的基础上,通过适量的钻探、试验等相关手段查明水库库区、坝区的岩溶水文地质条件,对拟建水库成库条件进行分析论证。分析认为水库坝两岸山体雄厚高陡,山脊高程以及冲沟沟源高程远高于水库正常蓄水位,因此,水库地形封闭良好,具备成库条件;左右岸邻谷可溶岩分布高程高于水库正常蓄水位且地下分水岭的水位高程高于水库正常蓄水位,水库不存在向左右岸邻谷渗漏的可能。坝址区河谷呈“U”型河谷,谷坡较陡,由于坝址下游河床附近溶洞、岩溶泉均有发育,水库蓄水后存在顺层面、裂隙等结构面与下游溶洞、岩溶管道连通而产生裂隙性渗漏以及岩溶渗漏的可能,建议进行坝基、坝肩的防渗处理。

Located on the southwestern edge of Sichuan Basin in the Delta Between Min River, Dadu River and Jinsha River in the upper reaches of the Yangtze River, the reservoir is a medium-sized source of water for regional irrigation and town water supply. On the basis of karst hydrogeological survey and geological mapping of the reservoir, the karst hydrogeological conditions of the reservoir area and the dam area are found out by appropriate drilling, testing and other relevant means, the conditions for the completion of the proposed reservoir are analyzed and demonstrated. It is considered that the height of mountain crest and the height of gully source are much higher than the normal water level of the reservoir the water level of the underground watershed is higher than the normal water level of the reservoir. There is no possibility for the reservoir to leak into the adjacent valley. The valley of the dam site is U-shaped and the valley slope is steep. Because the karst caves and karst springs are developed near the riverbed downstream of the dam site, after impoundment of the reservoir, there exists the possibility of fissure leakage and karst leakage due to the connection of bedding plane, fissure and other structural planes with karst cave and karst pipeline downstream.