GFWAust were appointed to grout the rock to seal off water flows into the basement excavation and to provide stability to the overlying sand to enable excavation to proceed.
Asheville Constructions were awarded the job of redeveloping the site at 71 Yarranabbe Road. There are height restrictions on the property and so a basement excavation was required. The property is close to the harbor with a 2m covering of sand over weathered sandstone. The required basement level was 4m below ground level.
All access to the site for construction equipment and materials was by barge.
Grouting of the rock was carried out around the perimeter of the basement through steel standpipes to a depth of 5m. Grouting was carried out with stabilized GP Cements. It was intended to use permeation grouting with microfine cement to stabilize the sand layers, but these proved to be too silty and clayey for permeation grouting and a soil mixing arrangement was carried out with the drill rig at 500mm centres which proved to be successful.