by nature'


For the municipality of Groningen we drilled a GRP nut sewer ⌀ 1100 mm of 900 m. The project is a preparatory part of the Ring Zuid approach (ARZ). ARZ is a project of the municipality of Groningen, the Province of Groningen and the State, for the conversion of the Ring Zuid (N7).



Gemeente Groningen
Implementation period

Bore Lenght

900 m

Bore Cross-section

Ø 1100 mm


We used the closed front technique, or microtunnelling, to install the sewer at a depth of approximately 5.5 m below groundlevel. In the route that runs from Paterswoldeweg and Donderslaan around Vrijheidsplein to Concourslaan, we have constructed 11 temporary sheet pile walls (low vibration), in which the drillings will later be connected to inspection pits. The microtunneling technique is very suitable for this because of the high accuracy and because it allows drilling below groundwater level. We limited the inconvenience for businesses and residents by making smart use of the environment, installing the sheet piles with low vibration and limiting drainage as much as possible. VLTT carries out the entire process from detailed design commissioning of the sewage system.
Special Circumstances
The plan ensures that traffic flows more smoothly and that all destinations in the city are more accessible. The road will be better integrated into the environment. That improves the quality of life. The road will also be made safer.