Soil remediation and construction pit work: Specialist earthwork

At the site where Waterside II was to be built, the soil was heavily contaminated. Specialist in ground, road and hydraulic engineering Halek Oudewater was called in to remediate the contaminated soil and prepare the construction pit for the concrete builder.

On the site where the project is being built, there was previously a creosote sorting plant. Halek Oudewater remediated the entire site and removed more than 8,000 tons of contaminated soil. The company then excavated the underground parking basement of more than 20,000 m3. "The soil and groundwater were seriously contaminated to a very great depth," says Wesley van den Hadelkamp of Halek Oudewater. "There had already been a remediation plant on that site to purify the groundwater. When we started work, the groundwater was not clean, but it was manageable."

On the basis of an available investigation report, for which samples were taken from various places on the construction site, Halek sat down with the client. "Just indiscriminately excavating three meters of soil and disposing of it as contaminated soil is very costly. Together with the research firm, we came up with a better implementation plan. We mapped the area well and chose to excavate in phases. That way we could reuse more clean soil or dispose of it as clean soil, which is much cheaper." A total of 20,000 solid cubic meters of soil were disposed of in various quality classes. 

The construction pit was completed tight, level and dry for the concrete builder. To ensure the pit would stay dry, Halek laid a drainage system below groundwater level. "Then the pile drivers could get to work and then we dug out the space around the piles again so that concrete could be poured. This work requires a lot of coordination, so no one gets delayed. Once the walls are in place, we will come and pour them." Finally, Halek designs and installs the exterior sewers. The company also takes care of furnishing the outdoor space.