闸站基坑开挖过程中的降水问题重要且复杂。采用“大井法”和数值模拟2种方法,对引江济淮工程中凤凰颈泵站改造的基坑涌水量进行了计算。基于三维渗流模型对基坑降水方案作了优化研究,对比分析了降水井的空间布置和井深度变化对基坑降水效果的影响,并综合考虑了工程经济性和施工便捷性,最终得到了推荐的降水方案。通过对各降水方案的分析可知:在基坑降水满足降深要求的前提下,降水井空间分布越均匀,各井抽水量的差距越小,有利于统一的水泵配购;将降水井布置在基坑周边,避免在基坑内部布井,能够减小对施工的干扰,但会显著提高总抽水量;降水井深度越大,需要布置的降水井数目越少,基坑总抽水量越大。该研究为闸站基坑降水方案的优化提供了良好的思路和范例。

The dewatering for foundation pit of sluice station is a significant and complicated issue. The water inflow volume of the foundation pit of Fenghuangjing Pump Station reconstruction for the diversion project from Yangtze River to Huaihe River was calculated using both the “large well method” and the numerical simulation method. The dewatering scheme was optimized via 3D seepage simulation, and the influences of the spatial arrangement of dewatering wells and the well depth change on the dewatering effect were compared and analyzed. A dewatering scheme was finally recommended in consideration of both economy and construction convenience. Under the premise that the dewatering meets the requirements of depth, the more uniform the spatial distribution of dewatering wells, the smaller gap between the pumping volumes of each well, the more conducive to unified pump allotment. Arranging the dewatering wells around the foundation pit and avoiding the layout of wells inside the foundation pit can reduce the interference to the construction, but can also raise the total pumping capacity. The greater the depth of the dewatering well, the greater the total pumping amount, and the fewer the number of dewatering wells that need to be arranged.