浅谈小湾大坝帷幕灌浆施工工艺

Brief Discussion on Construction Technology of Curtain Grouting in Xiaowan Dam

帷幕灌浆在坝基防渗、河堤防渗处理方面得到了广泛的应用,但因具体工程规模及地质构造不同,灌浆施工工艺不尽相同。世界最高的双曲拱坝云南小湾电站,因基岩有隐微裂隙发育且高水头,防渗标准高,文中对其灌浆设计从开工条件、浆孔分布、施工工艺流程、单孔施工流程、钻孔冲洗和灌前压水试验、灌浆质量检查等方面作了详细论述。分析表明,对于此类高水头且基岩裂隙发育的坝基,应首先对施工工艺进行评价,进而可采取特殊措施。从声波测试成果看,灌后较灌前波速普遍提高,说明灌浆使岩体间裂隙得到有效的填充,岩体密实度加强,证明小湾大坝坝基帷幕灌浆效果可以达到设计要求。

The curtain grouting is widely used in the seepage control for a dam base and river levee,which is different in construction technology.The design of curtain grouting in Xiaowan Hydropower Station of Yunnan is discussed here in detail,including the working conditions,the distribution of the grout holes,the construction technology and process,the construction process of the single hole,the boring washing,the water pressure test before grouting,the checking for the grouting quality and so on.The analysis results indicate that for this kind of dam base,the construction technology should be evaluated first,and furthmore the special measures should be adopted.It is showed from the sound wave tests that the grouting makes the cracks between the rock masses filled effectively,and makes the compactness of the rock masses strengthened,so as to prove that the effect of curtain grouting in Xiaowan dam could meet the requirements of the design.