Case Study: Installation of multiple deep wells for the realisation of a construction pit of 8m. The project was carried out on a historically polluted site with a difficult geological setting (blocking natural groundwater flow, multiple aquifers with low permeability, settlement- sensitive).
Our solution: To take care of the pollution, a temporary remediation drain was installed with short vertical filters.
After the remediation was completed, several combi-vacuum deep wells were installed in order to be able to drain the various aquifers. By placing a main source with one filter element and ancillary source with multiple filter elements in the same borehole, we succeeded in pumping out several less permeable soil layers alternating with poorly permeable soil layers.
The construction site is located across the old valley of the Maalbeek, which is filled with alluvial deposits (mainly gravel and clay) and is very sensitive to settlement. Due to the great danger of settlements, it was decided to make a wall into Ypresian clay, thereby closing off the natural SW-NE groundwater flow through the valley. For this, we placed passage to collect water on one side of the construction site and to infiltrate it on the other side.