宝珠寺水电站二期上游围堰覆面式复合土工膜防渗结构研究

Type of Upstream Cofferdam in the Second Period at Baozhusi Hydropower Station

二期上游围堰原设计为粘土心墙沙砾料堰，经研究修改为覆面式复合土工膜防渗结构石碴堰。本文简述复合土工膜选型及铺设位置的确定，室内力学性质试验和现场工艺试验取得的主要成果。重点论述覆面式复合土工膜防渗结构的组成，设计任务和计算方法。首次提出考虑孔隙周边松驰时垫层允许孔隙尺寸的汁算方法。分析取得的社会经济效益并得出可推广应用于类似工程的结论。

The upstream cofferdam in second period was originally designed as a sand and gravel dyke with clay core. After analyzing,it was modified to a ballast dyke with composite geotechnical membrane of covering surface type. The paper briefly describes type selection and location of the membrane. The main results achieved from laboratory mechanical property test and field technique test are given. Compositions,design task and compuatation methods for the composite geotechnical membrane of covering surface type as impervious structure are discussed mainly. Computational method is presented first for permissible pore size of cushion when peripheral relaxation of pore has been considered from analysis,it is shown that both social and economical benifits will be gained and it is concluded that the method should be applied for the similar project.