Industrial Development Board for NI
The contract was for the enabling works necessary to permit the construction of a new factory on the Springvale Business Park at Springfield Road, Belfast.
The Works included:
The construction of a 3,000 mm diameter diversion culvert, some 256 metres in length, through filled ground and silty clays at a depth of some 8.5 m.
Due to the nature of the ground and to the depth required we put forward an alternative design for tunnelling the culvert using a conventional shield and 3.1 m diameter precast concrete segmental lining. This resulted in considerably less site disruption and a resultant saving in cost to the client.
The construction in reinforced concrete of inlet and outfall chambers to connect the tunnel to the existing stream and an access chamber from where the two tunnels drives of some 200 m and 56 m commenced.
The tunnels were driven through mixed strata consisting mainly of fill material overlying clay. Considerable amounts of groundwater were encountered, at times requiring dewatering to ensure the stability of the face.
The bulk of the spoil from the tunnel was stockpiled on site and re-used to fill in the redundant stream bed after the diversion had been completed.
The construction of a 92 m long steel sheet piled retaining wall to secure the perimeter of the new site.
Some 260 tonnes of PC2 coated Larssen 6 sheetpiles of varying lengths were driven by telescopic leader rig.
The piles were driven into marl and this required the pre-auguring of the line in order to permit sufficient penetration.
The completed pile wall was secured by ground anchors.