Pipe ramming was selected to install the pipes underneath 11m of existing building, and a Koloss rig from Tracto-Technik was supplied to the job.
Before ramming could begin, building foundations had to be chiselled out to a depth of 2 meters using a hydraulic hammer. Then the 6m long steel pipes were positioned and aligned. Then the foundation area around the pipe was refilled with gravel concrete, securing the outer wall of the building and preventing the house walls from crumbling due to ground vibration during the pipe driving process. To make pipe jacking through the gravel concrete possible at all, the pipes were also bubble wrapped.
The geology was sandy and gravelly boulder clay, some 12m3 of which needed to be cleaned out of the pipes with a suction excavator after the job was complete.
