超深振冲碎石桩施工技术及应用

Construction Technology and Application of Ultra-deep Vibro-replacement Stone Columns

金沙江上游拉哇水电站上游围堰地基覆盖层最大深度超过65 m,为保障围堰上下游堰坡和深基坑开挖边坡稳定安全,须对堰基采取加固处理措施。通过采用SV70碎石桩机和伸缩导杆连接振冲器,成功实现了65 m超深振冲碎石桩施工,是目前国内外大规模施工的最深振冲碎石桩。检测成果表明,在采取加固处理措施后,围堰基础明显改善了抗液化性能,提高了承载力和抗变形能力,振冲碎石桩透水性良好,为拉哇水电站围堰及深基坑边坡安全稳定提供了保障。

The maximum depth of the upstream cofferdam foundation overburden of Lawa Hydropower Station on the upper Jinsha River exceeds 65 m.In order to ensure the stability and safety of upstream and downstream slopes of cofferdam and deep foundation pit slope,the foundation of cofferdam must be reinforced.By using SV70 gravel pile machine and telescopic guide rod to connect vibroflotation device,the construction of 65 m ultra-deep vibro-replacement stone columns are successfully realized,which is the deepest vibro-replacement stone columns constructed on a large scale at home and abroad at present.The test results show that the anti-liquefaction performance,bearing capacity and deformation resistance of cofferdam foundation are obviously improved after the reinforcement measures are taken,and the vibro-replacement stone columns have good water permeability,which provide a guarantee for the safety and stability of cofferdam and deep foundation pit slopes of Lawa Hydropower Station.