APK Group bores 372-metre long passage up to 35 metres deep beneath the centre of Houthalen

Commissioned by Fluvius, APK Group has carried out a directional drilling operation measuring approximately 372 metres in length and up to 35 metres in depth in the centre of Houthalen. Via this underground conduit, Fluvius's medium-voltage and fibre-optic cables will later be able to cross the tunnel zone of the North-South connection without compromising the reliability of the grid.

For the redesign of the North-South connection, a tunnel is being built in the centre of Houthalen, right at the location where important utility lines belonging to Fluvius are situated. Routing the cables around the tunnel would mean extra cable length and greater voltage drop. Therefore, Fluvius opted for an underground crossing near Dorpsstraat. This is deep enough not to obstruct the future tunnel works.

Exceptionally long and deep
A borehole of this length at this depth is not an everyday task. Even in the design phase, a great deal of attention was paid to an optimal and conflict-free drilling alignment. Account had to be taken of existing utility infrastructure and the planned tunnel. Moreover, a bundle of seven Ø200 mm HDPE pipes had to be pulled in in a single movement. This called for a large bore diameter and a precise design.

APK Group welded the entire 372-metre pipe bundle themselves and also assembled it themselves. For the pilot bore, the team used a Brownline gyro steering system. This enabled the route to be accurately followed, even at great depth and over a long distance. Afterwards, the borehole was reamed to 700 mm and the pipe bundle was pulled in. The drilling was carried out using a Vermeer D100 HDD drilling rig, which is built for long and technically complex routes.

Less disruption, less waste
Because the works took place right in the centre, minimising disruption was a priority. Thanks to the trenchless technique, the route did not need to be broken up. As a result, traffic, local residents and businesses experienced as little trouble as possible. Everyone involved was kept informed of progress in a timely manner via the Minder Hinder app. In addition, an MR100 Mix Recycling Unit ensured that the drilling fluids, water and bentonite, were recovered and reused. This limited both the consumption of raw materials and the amount of waste that had to be disposed of.

Collaboration within the group
For the signage, the Drilling team worked with Verfaille, which is also part of APK Group. ‘This project demonstrates the power of collaboration within APK Group,’ says Manu Van Gompel, client manager at APK Group. ‘By combining the expertise of our drilling crews, welders and signage specialists, we were able to carry out a complex drilling operation with minimal disruption to the surrounding area.’

Future-proof
With the new holding siding, space has been made for the infrastructure works of the North-South connection. At the same time, the project contributes to a robust and future-proof energy network in the region.