皇庄中闸兴建于1975年,因在历次大洪水中多次出现管涌等险情,属病险涵闸。2005年,该闸纳入了南水北调中线一期汉江中下游部份闸站改造工程,改造方案为原址拆除重建。实际施工过程中,由于汉江水位居高不下,基坑开挖未达到设计高程便出现不同程度的翻砂鼓水而影响施工。为保证闸基的拆除开挖和底板混凝土施工,设计采用基坑降水措施将基坑中心地下水位降低至底板以下0.5 m。设计井点共30口,井点间距堤内为15 m,堤外为30 m。施工实践表明,整个施工过程中,地面干燥无水,证明了降水设计的合理性。%Huangzhuangzhong Sluice was built in 1975, it was assessed as a dangerous sluice for many piping occurrences in history floods. The sluice was incorporated into reconstruction program of partial sluices in downstream reach of Hanjiang River in coordination with the construction of Middle Route Project of South-to-North Water Diversion, and a solution of in-situ remo-ving and reconstructing was proposed. During construction, due to high water level of Hanjiang River, the sluice foundation con-struction was disturbed by piping and seepage problems even before the excavation reached the designed elevation. For ensuring foundation construction, a dewatering design solution was proposed as 30 wells with interval of 15m inside the pit and interval of 30m outside the pit, by which the groundwater level was controlled 0. 5m below the foundation bottom surface successfully. The engineering practice show that the ground is dry during construction process and the dewatering design is reasonable.
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