Soil Mixing and Dewatering with Artificial Recharge for the Construction of a Mutifunctional Complex

The new multifunctional complex “HOF VAN SAEYS” was built on Dijkstraat in Dendermonde. The complex includes a parking lot consisting of 2 underground levels with 9 lift wells. Due to the sensitivity to settlement of the underground and the adjacent abbey garden, the groundwater lowering is carried out within earth-water retaining walls (soilmix walls). No natural horizontal impervious layer was accessible at an economically reasonable depth. The groundwater lowering is therefore carried out with deep wells and artificial recharge wells: 22 submersible pumps pull the groundwater out from the construction pit. These submersible pumps then push the groundwater to 22 artificial recharge wells that send it back into the ground. The project employs a dewatering system with submersible pumps and artificial recharge wells located immediately behind the partial retaining walls. The soilmix walls are not anchored in the natural horizontal impervious soil layer. This method allows groundwater to be pumped out of the excavation and reinjected, forming a closed water cycle. This significantly reduces the amount of water pumped and discharged into the city's wastewater system and the risks of settlement. This project demonstrates the effectiveness of recharge techniques combined with retaining walls for construction projects in sensitive areas, enabling sustainable and environmentally friendly management of groundwater resources.