西湖调蓄水库堤基地质问题及处理措施探讨

Disscusion on Geological Problems for Dam Foundation of Xihu Storage Reservoir and Its Countermeasures

西湖调蓄水库是调节南水北调中线和引黄来水的平原水库,堤基主要为第四系全新统壤土、砂壤土、粉细砂层,其中粉细砂、砂壤土层的渗透系数较大,库区存在多条古河道,堤基部位有可能产生渗漏、渗透变形等地质问题。库区地震基本烈度为7度,经判别,水库蓄水后砂壤土、粉细砂层存在地震液化问题,必须对堤基采取适当处理措施才能保证水库安全蓄水。

Xihu Storage Reservoir is a plain one which regulates the water from middle route of South - to - North Water Transfer Project and Huang River Water Transfer, its base foundation is made up of Holocene loam, sandy loam, silt and fine sand in quaternary. As we known, the layers of sandy loam, silt and fine sand have large permeability coefficients, meanwhile, several ancient river channels exist in reservoir area, which may cause many geological problems, such as leakage, seepage deformation and so on. Here the seismic basic intensity is 7 - degree, after the analysis and estimation, the earthquake liquefaction may occur in loam, silty and fine sand layers after water impoundment in the reservoir, so some countermeasures must be carried out for dam base to ensure the safety of water impoundment.