Abstract: The foundation of the relocated road in the underground powerhouse project of Jinqiao hydropower station in Tibet is located on the floodplain and riverbed of Yigong Zangbu river. Its lithology is sand gravel stratum, base is metamorphic quartz sandstone and sand lenses exist in some sections which result in high standards for seepage prevention and difficulties in construction of high pressure jet grouting cutoff wall. During the road construction, the relevant parameters of high pressure jet grouting cutoff wall were adjusted based on the construction process and the test and monitoring data showed that the wall was well cemented and continuous. Its effect could meet the design requirements and it went through the flood happened in 2017 whose return period was longer than 20 years which proved the effectiveness of the high pressure jet grouting cutoff wall.

Key words: high pressure jet grouting cutoff wall, Jinqiao hydropower station, relocated road

摘要： 西藏金桥水电站地下厂房工程改线公路基础布置在易贡藏布江河漫滩及河床上，地层岩性为河床砂卵砾石层，基底为变质石英砂岩，局部地段存在砂层透镜体，防渗标准要求高，高喷成墙难度大。结合工程实际，在高喷过程中不断调整和修正相关参数，从孔压水检测、墙体开挖检测及高喷过程结果资料分析，发现防渗墙墙体胶结良好、连续，高喷防渗墙灌浆效果达到设计要求，并经受了2017年发生的超重现期20年洪水考验，应用效果显著。

关键词: 高喷防渗墙, 金桥水电站, 改线公路