As much as 207,000 meters of vertical drainage for the New Lock in Terneuzen

Drainage accelerates the settlement process of soft soils

"We install vertical drainage and apply preloading to accelerate the soil consolidation process," Van der Veen continues. "By doing so, we promote the settlement of the soft subsoil. The drains allow water to come to the surface and flow away from there."

Settlement periods from four months to a year

Applying drainage accelerates the settling process with settlement periods ranging from four months to a year. "At the New Lock in Terneuzen, we are applying vertical drainage in four phases. We completed the first phase at the end of last year. We have now installed about 35,000 meters of the total 207,000 meters of drainage."

The drains are "flattened" tubes delivered in 300-meter rolls. They are inserted into the ground with specially adapted excavators. Van der Veen explains, "We modify our equipment ourselves. Besides equipping the excavators with a special broker, we also modify the hydraulics so that they are suitable for the forces and speeds required to install vertical drains. We have specialists with years of experience for that.

Working from a GPS system

"At the New Lock in Terneuzen, we are standing on a 'work floor' of sand. Water comes up through the drains and flows off into the draining sand layer. A lot of water also evaporates in the summer," Van der Veen continued. "Our drivers work with an advanced GPS system. This shows exactly where the drains need to be installed and we can provide detailed 'as built' information to our client."

In Terneuzen, Wicks has already installed drains along east side of the middle lock. "The total drainage work should be completed in the first quarter of 2023. We have just completed the fourth quarter of 2020 and will enter again in the first quarter of 2022. It's great to be able to contribute to such a big project!" said Van der Veen.