巴郎口水电站土石坝填料工程特性试验分析

位于大渡河一级支流上的巴郎口水电站为闸坝引水式。考虑到砂卵石填筑料中粒径小于5mm的P5含量偏高而影响坝体稳定性,对厂房边坡砂卵石填筑料开展了碾压试验。根据现场密度及含水量测试、场地沉降观测等,确定合适的铺层厚度为97cm。并取坝体填筑料在室内进行了颗分、击实、渗透和大三轴剪切试验。颗分试验表明填筑料级配良好,满足土石坝设计要求;击实试验得到填筑料的最优含水量和最大干密度分别为5.32%、2.42gcm-3;渗透试验测得砂卵石平均渗透系数为2.42210-2 cms-1;大型三轴试验获得砂卵石强度参数为=37.711、c=0。结合现场碾压试验和室内试验成果,还对巴郎口水电站土石坝坝体进行了渗流稳定计算,复核了巴郎口水电站土石坝坝体的沉降、应力、渗流和稳定性等,为土石坝坝体的长期安全运行提供了重要依据。

EXPERIMENTAL ANALYSIS FOR ENGINEERING PROPERTIES OF EMBANKMENT FILLING MATERIALS AT BALANGKOU HYDROPOWER STATION

The Balangkou hydropower station locates on the tributary of the Dadu River and is a diversion station. The content of the sand and gravel filling materials with P5(particle size less than 5mm) is relatively high, which may influence the stability of dam. The rolling test is carried out in the construction site. This test determines the suitable filling thickness as 97cm. And the density, moisture content and settlement are measured as well during the rolling test. In addition, the grain content test, compaction test, penetration test and large triaxial test are carried out in laboratory. The grain content test shows that the sand and gravel are well graded and can meet the embankment dam design requirements. The optimum water content and maximum dry density are 5.32% and 2.42gcm-3 respectively. They are determined with compaction test. The average permeability coefficient is 2. 42210-2cms-1, which is obtained with penetration test. The strength parameters of the filling materials are =37. 711 and c=0,which is got with triaxial test. According to the test results, this study also checks the dam settlement, stress, seepage and stability comprehensively. The test results provide some guides for the long-term operation of the Balangkou Hydropower Station.