In the dam foundation curtain grouting of Dagangshan Hydropower Station, extremely abnormal dense slurring retur-ning occurred. The grouting was not satisfying after the replacement of new slurry and improvement of grouting pressure. The in-jection ratio was more than 10L/min even if the slurry was replaced twice. The analysis showed that micro-fissures existed in strata and the slurry with coarse particles was difficult to be grouted. In view of the causes of dense slurry returning, multiple times of grouting tests with fine cement were conducted and the grouting parameters suitable to this stratum were obtained. Based on test result, new grouting scheme was made. The new grouting scheme solved the dense slurry returning and guaranteed the e-conomic goal and construction progress of the project.%在大岗山水电站河床坝基帷幕灌浆施工中，出现了极为异常的回浆返浓现象，在置换新浆和提高灌浆压力后改善效果仍不明显，即使置换两次新浆，灌浆结束时注入率仍然超过10 L/min。通过分析认为，回浆返浓的主要原因是地层中存在微裂隙，使颗粒较粗的水泥难以灌入。对此开展了多次细水泥灌浆试验，获取了适合该地层的灌浆参数，并依据试验结果制订了灌浆方案，解决了回浆返浓问题，保证了工程建设的经济与进度目标。
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