A VAST MULTI-LEVEL sport, leisure and retail complex being built on a former opencast coal site in Yorkshire will be supported on an 'underground forest' of precast driven piles made and installed by Aarsleff Piling.
The £31M development, at the former Glasshoughton mine near Castleford, will contain a real snow ski slope, an ice wall and numerous other leisure and entertainment facilities and retail outlets.
Design and build contractor Shepherd Construction is building the scheme for client Xscape.
For the £400,000 six-and-halfweek contract Aarsleff installed about 1,600, 250mm and 300mm square, precast concrete piles varying in length from 6m to 13m.
The piles were made by Aarsleff's subsidiary Centrum Pile.
Piles were installed in groups of two to eight on a 7.5m square grid with about 1m between each pile. Three Banut 500 hydraulic rigs were used to drive the piles through 5m to 12m of well compacted made ground, founding just into the underlying Mercia Mudstone. Each rig drove an average of 20 piles a day.
A fourth rig drove Larssen LX20 steel sheet piles for the cofferdam to support the excavation for the ice wall.
Aarsleff worked closely with Shepherd at the pre-contract stage, carrying out probing around the site, installing 10 test piles and pre-augering 24 holes.
Information gained was used in Shepherd's final pile design and to determine pile lengths, the suitability of driving in the compacted dense ground and to locate a high wall from the opencast coal workings.
The trial piles were dynamically tested to confirm the building loadings. It was found that working loads for the smaller 250mm square section piles could be increased by 20% to 600kN. The pile cap design was also changed and improved.
Noise & Vibration Management monitored test piling to confirm that operations were within the contract's specified limits.
The Xscape development is on schedule to open in September next year.