西藏旁多水利枢纽坝基超深防渗墙施工技术

Technology of extra-deep cutoff wall construction of dam foundation of Pangduo Hydropower station in Tibet

在西藏拉萨河旁多水利枢纽坝基158.47 m深防渗墙的施工中,结合地层、施工强度、设备能力等综合考虑,采用"钻抓法"局部结合"钻劈法"造孔成槽。为提高泥浆固壁效果,选用了一种新型的JCJ/MMH正电胶泥浆;墙体连接施工采用接头管法。对施工过程中松散易塌地层、粉细砂地层、孤石层的处理,孔形、孔斜的控制等作了详细介绍。可供同类工程参考。

The deep cutoff wall with the depth of 158.47m of the dam foundation of Pangduo Hydropower station on Lasa River in Tibet is constructed by considering the factors such as the stratum, construction intensity and capacity of equipment compre- hensively. We adopted drilling - grabbing method, together with drilling - splitting method partly to make the holes into grooves. The new - type JCJ/MMH drilling slurry was selected to improve the slurry effect of fastening to the wall and the jointing pipe method was adopted during the construction of connecting walls. Furthermore, the treatment of loose and easily - collapsed stra- tum, silty sand stratum and boulder stratum during the construction, as well as the hole shape and hole deviation are all intro- duced particularly. The construction technology can be a reference for similar projects.