桥巩水电站二期围堰堵漏技术研究

Leakage Control of Second-stage Cofferdam for Qiaogong Hydropower Station

广西桥巩水电站二期围堰为土石围堰,上游围堰采用粘土铺盖结合土工膜防渗,下游围堰采用高压旋喷结合静压注浆防渗。施工完成后抽水,基坑内的漏水量达到4000 m3/h以上,需进一步进行防渗处理。根据围堰的地层特点,提出了水泥膏浆灌浆防渗处理方案,对大漏量孔段采用了膏浆结合级配料的堵漏灌浆处理方法,施工实践表明,其防渗堵漏效果良好。工程经验可供类似工程参考和借鉴。

The second-stage cofferdam of Qiaogong Hydropower Station is an earth-rock cofferdam. 21ae clay blanket combined with geomembrane was used for seepage control in the upstream of the cofferdam, and the high jet grouting and static pressure grouting were used in the downstream of the cofferdam. However, the amount of leakage still exceeded 4 000 m^3/h inside the foundation after the construction, which needs a furthor treatment. According to the characteristics of the cofferdam, the grouting method of cement-paste slurry combining with aggregates is used to plug a large amount of leakage. Results show that the method adopted here has good effect for leakage control, which could provide a reference for similar projects.