复合含水层地区深基坑降水三维渗流场数值模拟——以上海环球金融中心基坑降水为例

长江三角洲分布有巨厚、松散的第四纪沉积层,地下含水系统为一复合含水层系统,深基坑降水一般采用非完整井,且由于深基坑周围连续挡水墙难以深入含水层底板,所以其地下水渗流场变化极其复杂,具有明显的三维流特征。本文以上海环球金融中心深基坑降水为例,采用数值模拟方法,模拟了在多层含水层复合存在、含水层最深底板埋深达149m、基坑周围挡水连续墙埋深达34m、基坑内地下水位降深达26m的情况下的地下水三维渗流场特征,并以此为据确定出了该基坑降水的最优化方案。

NUMERICAL SIMULATION OF THREE-DIMENSIONAL SEEPAGE FIELD OF A DEEP FOUNDATION PIT DURING DEWATERING IN A COMPLEX COMPOSITE AQUIFER SYSTEM——CASE STUDY OF DEWATERING OF A PIT AT THE SHANGHAI FINANCE CENTER

Multi-layer loose and thick Quaternary sediments in the Yangtzi River delta create a complex aquifer system.Partial pumping wells used in dewatering project and the diaphragm wall not attached to the bottom of layer around pits result in a very complex characteristic of three-dimensional groundwater seepage in the foundation pit.In this paper authors use the dewatering of the foundation pit at Shanghai Finance Center as a case study to demonstrate how the three-dimensional finite-difference numerical method can be used to characterize the groundwater seepage in the foundation pit.It is a multi-layer aquifer system with a confining layer at a depth of 149 m,a pit’s diaphragm wall at a depth of 34 m and an anticipated water level drop of 26 m within the pit.An optimized method for dewatering of the foundation pit is eventually derived.