Large Core Drilling Through a 70 cm Manhole

When a new sewer pipeline connection had to be made to an existing reception chamber in Ghent, the project presented a series of unique challenges.

A circular opening with a diameter exceeding one metre had to be created through heavily reinforced concrete and secant piles. In certain areas, the chamber wall reached a thickness of up to 80 cm.

However, the greatest challenge was not the drilling itself. Every piece of equipment first had to pass through an access manhole measuring only 70 cm in diameter.

Success depended on preparation. In cooperation with Adamas (supplier of diamond drilling and cutting equipment), a trial setup was designed and tested beforehand. This allowed us not only to verify that all equipment could safely pass through the restricted access point, but also to optimise the positioning of the core drilling system. By carefully planning the setup in advance, multiple reconfigurations underground were avoided, significantly improving efficiency and execution time.

The operation was carried out successfully, with all equipment lowered through the manhole using our 20-ton meter crane truck, one of the additions to our fleet in 2026. Once on site, the planned core drilling and opening works were completed safely, accurately, and according to schedule.