The Luton Town Centre Transport scheme aims to provide the missing link for the town's inner ring road system. A new link road has been constructed to provide an improved east to west route for vehicles. To facilitate this, retaining walls were required throughout the scheme to support adjacent embankments.
To the north side of the wall two private properties were located, one of which although not listed was of historic interest as part of the industrial heritage of Luton. The town's railway station and Network Rail's permanent way were located on the south side of the wall. Sections of the work that fell within the rail envelope had to be completed during rail possession periods.
The client's design for the retaining walls specified the use of steel sheet piles driven 6.5m - 7m into the underlying structure-less chalk bedrock, using sustainable techniques such as noiseless and vibration free hydraulic pressing.
VolkerGround Engineering as part of their subcontract works to main contractor VolkerFitzpatrick mobilised a self-contained Kowan WP 150 Stillworker Hydraulic Press, which was located on the pile sections themselves utilising reaction from previously installed piles to push subsequent sections in to the ground. Where the ground was more resistant to penetration, the pressing was supplemented through high pressure water jetting methods to loosen the underlying material.
In the course of its works at Luton, VolkerGround Engineering installed 188 plan metres of AU14 section sheet piles up to maximum lengths of 10.3m using this technique from the beginning of September to December 2013.