两河口水电站大坝岸坡卸荷基础帷幕灌浆施工技术研究及应用

Construction technology and application of curtain grouting for unloading foundation of Lianghekou hydropower station

针对两河口水电站岸坡砂板岩卸荷基础帷幕灌浆施工期出现的抬动、劈裂、串冒漏浆现象,以及由此引起的群孔效应导致水泥灌浆效果无法达到设计要求、施工效率较低等技术难题,通过调整优化设计参数及施工方案,采取降低灌前裂隙冲洗和压水试验压力、降低浅层灌浆压力及检查孔压水试验压力、加长孔口管、抬动临界流量控制灌浆、改性环氧浆材化学灌浆等综合工程技术措施,成功地解决了卸荷岩体帷幕灌浆合格率低的技术难题,灌浆效果良好,对其他类似工程的设计施工有一定的参考价值。

During the construction of curtain grouting for sandy slate unloading foundation of Lianghekouhydropower station,the uplift,splitting,leakage of grouting and group effect of holes are easy to occur.The resulting group hole effect leads to the technical problems that the cement grouting effect cannot meet the design requirements and the construction efficiency is low.By adjusting and optimizing the design parameters and construction plans,the comprehensive engineering and technical measures such as reducing the pre-grouting pressure of crack flushing and water pressure test,reducing the pressure of shallow grouting and the pressure of water pressure test after grouting,lengthening the orifice pipe,using the critical flow control grouting,and modified epoxy slurry chemical grouting are adopted.The technical problem of low qualified rate of uploading curtain grouting is successfully solved and the grouting efficiency is good,which has certain reference value for the design and construction of other similar projects.