西藏拉洛水利枢纽工程沥青混凝土心墙坝高细粒含量过渡料应用研究

Study on application of high-content fine-grained transition material for asphalt concrete core dam of Laluo Hydro Project in Tibet

西藏拉洛水利枢纽工程大坝沥青混凝土心墙两侧过渡料设计,采用合格坝壳料剔除粒径大于80 mm后余料。现场料场复勘发现,余料小于5 mm粒径含量大多在50%左右,不能满足小于5 mm粒径含量为25%~40%的规范要求,需要对现场余料进行优化。对细粒含量偏高的过渡料进行了物理力学特性试验、渗透稳定试验,分析了坝体应力变形。结果表明:过渡料抗剪强度指标良好,坝体满足渗透稳定性要求和反滤过渡关系,坝体应力及变形符合一般土石坝规律,细粒量偏高对坝体应力及变形影响小。对大坝过渡料进行了优化,水库下闸蓄水后,大坝运行状况良好,相关设计研究成果和思路可供其他工程借鉴。

The transition material on both sides of the core wall of Laluo Hydro Project was acquired from the remaining qualified dam shell material after removing the grain with size larger than 80 mm.The field investigation showed that the content of grain size smaller than 5 mm was about 50%,which can’t meet the specifications requirement that the content of grain size smaller than 5 mm should be 25%~40%.So, the material should be optimized.The physical and mechanical properties test, seepage stability test of the transition material with high fine-grained content were carried out, and the stress-deformation of the dam was analyzed.The results showed that the shear strength index of the transition material was good, and the dam body met the requirements of seepage stability and filtration transition relation;the stress and deformation of the dam body conformed to the general law of earth-rock dam, and the high-content fine-grain transition material had little influence on the stress and deformation of the dam body.The transition material of the dam was optimized accordingly.The dam operates well after the impoundment.The related design research results and ideas can be used for reference by other projects.