Extraordinary drilling at Maastricht Station

In connection with the expansion of Maastricht Station, an all-encompassing casing pipe for pipes must be installed underground. The innovative trenchless pilot-controlled auger drilling technique is being used for this purpose.

Maastricht Station is expanding and also wants to be prepared for the future. Therefore, new underground pipes are needed. In September 2019, work will begin on laying a steel casing pipe containing several HDPE tubes. These will serve as casing pipes for fiber optic connections, water and power lines, among other things.

Steel casing pipe under 12 tracks through

Ronald van Krieken, director/co-owner of Holland Drilling, which specializes in the design and execution of various drilling techniques including horizontal directional drilling: "It involves a 70 m long steel casing pipe that runs under 12 tracks from the railroad yard to the central platform. This is special among other things because there is little workplace." The installation of this casing pipe is part of a larger project for which ProRail has engaged contractor Wallaard Noordeloos. To install the all-encompassing steel casing pipe with a diameter of 508 mm, the pilot controlled auger boring technique is being used. "We have several auger drilling machines with a capacity of up to 320 tons," explains Van Krieken. "Depending on the pressing force range (here 100 tons), we deploy the right machine. Because of ProRail's safety regulations, we fill the space between the steel casing pipe and the HDPE pipes with the cementitious filler Dämmer® to prevent subsidence of the track in the future."

Drilled steel casing pipe containing HDPE - tubes.

Supplying and pumping it is a specialty that the Cuijk-based company has in-house. This involves the use of a specially developed mix-pump installation in which dosing and mixing can be done to the nearest kilogram.

Geology complicates drilling

What further makes the work challenging is the geology consisting of marl, gravel and maas boulders that makes drilling difficult. Using the auger drilling method, the subsurface is traversed and the pipe pressed in horizontally according to the pilot drilling carried out beforehand. The released soil is discharged outside through the auger auger. The tolerance allowed necessitates a separate laser system combined with a camera for in the drill head. "The laser is in the starting pit from where we drill and focuses on the target in front of the drill head. The drill master can monitor from the drill pit down to the centimeter if something falls outside the drill line and can then make adjustments," Van Krieken said.