Farmyard underpassing with TERRA-JET DJ 10

Horizontal-Bohranlage, horizontal directional drilling © TERRA AG, Reiden, Switzerland
The district heating connection on a former farmyard in Upper Austria had to be newly installed. The connection needed to be laid in the shortest way diagonally across the farm and the adjacent forecourt. As a result a challenging drilling job was given particularly due to expected interference in the building in respect to the rebars in the floor plate and the fix installed metal racks.

The contractor Wagner Wasser & Wärme used his new horizontal directional drilling machine TERRA-JET DJ 10 to face that challenge. The rig was installed at the backside of the farm. From there the 54 m (180 ft) pilot bore underneath the building and the forecourt was realized. Finally a pipe bundle around the district heating pipe with outer diameter 162 mm (6.4”) was pulled back.

The HDD machine TERRA-JET DJ 10 is equipped with 2 m (6.6 ft) long drill rods, which allow a minimum bending radius of 25 m (82 ft). The torque of 1’800 Nm (1‘350 ft.lbs) and the thrust and backream force of 40 kN (4 tonnes, 8’800 lbs) allow bore channels up to ø 300 mm (12”t).

As expected, the locating underneath the building became a bit problematic with the imprecise, sometimes missing signals due to passive interference. But since there were no existing cables nearby and thanks to the relatively stable pitch signal it was possible to drill tolerably precise and underpass the farm.

Along with the district heating pipe ø 162 mm (6.4”) further preventive empty pipes were installed. In total a bundle of 5 pipes were pulled back, which required a backreaming of 280 mm (180 ft). Wagner Wasser & Wärme has a specifically equipped trailer that includes not only the mixing and pumping unit and drilling tools, but also the TERRA-JET DJ 10 for transport. That way they are efficiently organised for executing such pipe installation projects.

Gebäudeunterquerung, passage under building © TERRA AG, Reiden, Switzerland
speziell ausgerüsteter Anhänger, specifically equipped trailer © TERRA AG, Reiden, Switzerland
Bohrkopf in der Zielgrube, drill head in the target pit © TERRA AG, Reiden, Switzerland

Rohrbündel ø 280 mm, pipe bundle ø 280 mm © TERRA AG, Reiden, Switzerland


TERRA AG für Tiefbautechnik - Hauptstrasse 92 - 6260 Reiden - Schweiz - Tel. +41 62 749 10 10 -