Determination of groundwater pumpage for dewatering construction site of Happy complex in Tay Ho district, Hanoi

Abstract

Groundwater is unfavorable for construction activities, so groundwater dewatering or freezing needs to be carried out. The Happy complex is located in Tay Ho District, Hanoi city. The complex is to be constructed with 47 stations which are evenly distributed over a construction area of 10,000 m2 in the depth from 12.1 to 18.25 m below the ground surface. It is required to dewater groundwater to have the groundwater level to be 1.5 m lower the bottom of the stations. Vertical groundwater wells have been selected for the. The determination of groundwater pumping rates for the dewatering had been carried out by numerical modeling. GMS10.3.2 software had been used to model the groundwater flow using the MODFLOW modul. The modeling area is expanded to cover the construction site with dimensions of 370m x 420m. The grid cells are 4m x 4m. The groundwater pumping rates were determined by solving forward analysis of different options to select the optimal solution, which includes 29 pumping wells with the same well pumping rate of 1,040 m3/day. The lowered groundwater levels at all the construction stations have met the requirement.