Numerical approach for the optimal design of dewatering schemes for deep foundation pits

Abstract

Abstract In recent years, underground spaces have expanded widely in the urban zone. The appropriate estimation number of dewatering well with economical costs and securing soil stability at construction sites is challenging in designing pumping schemes. This paper aims to present the numerical approach for the optimal number of wells for designing a dewatering deep foundation pit. First, the estimated hydraulic conductivity was selected among the Theis, Cooper-Jacod, and reverse groundwater modeling methods. The estimated hydraulic conductivity via reverse groundwater modeling shows the lowest error with the monitoring pumping test. Second, hydraulic conductivity was input to groundwater modeling to estimate the groundwater level of four pumping schemes with the same total pumping rate (20 wells, 17 wells, 14 wells, and 13 wells). The number of wells was optimal from four random pumping schemes concerning the cost and the drawdown outside the pit. As a result, the pumping scheme with 16 wells is suitable, satisfying the cost and safety outside the drawdown of the foundation pit. The numerical approach could apply to estimate the number of wells for dewatering projects with economic costs and less impact on surrounding construction sites.