深基坑降水疏干过程中三维渗流场数值模拟研究

Numerical simulation study on 3-D seepage flow in deep foundation pit's dewatering and drying

运用潜水、承压水渗流理论和有限差分法,以及干湿单元、预处理共扼梯度算法,以上海环球金融中心塔楼深基坑降水为依托工程,对深基坑降水的三维非稳定渗流场的计算建模和降水疏干过程进行了数值模拟研究。利用5口井和8口井的群井抽水试验资料,对模型主要参数进行了校正及后继检验计算。在上述基础上对中心基坑水位降至-22m时井的布置方案进行了优化设计,同时分析了深基坑内外渗流场的变化,为深基坑降水设计和施工提供了依据。

By using the seepage theory of confined and unconfined, finite difference method, dry and wet elements and PCG, this paper studied the reasonable modeling and conducted analysis of the 3-D transient seepage in deep foundation pit＇s dewatering based on the project for the Shanghai Finance Center which is the highest building in the world. On the basis of analysis of 5 wells＇ and 8 wells＇ experiments of pulling, parameters of model were validated and identified, then through a further comprehensive sensitive feedback analysis and subsequence checking, 3-D seepage in deep foundation pit＇s dewatering and principles and methods of dewatering design were full demonstrated. What＇ s more, the article forecast the distributing characters seepage fields inward and outward of foundation pit when the water table reduced to -22m, which provided theoretical assist for deep foundation pit＇s dewatering and construction.