Prima Pearl Tower Development
Specialist foundation work was required for the new Prima Pearl Tower development in Melbourne. To facilitate the lift core construction on the project, jet grout columns were installed to act as a lateral base slab which supported a secant pile wall cofferdam.
Following the installation of trial columns to confirm column diameters and construction parameters, a total of 73nr 3.2m diameter columns were installed between 10 and 11.5m below current ground level to form the 28m x 16m base slab, using the Super-jet grouting system.
All columns were built with sophisticated instrumentation that monitors, controls and records the construction parameters to ensure the highest quality control standards are achieved, and records were maintained to verify the works complied with quality requirements.
The treatment zone was a highly plastic, silty clay material, known as ‘Coode Island Silt’. Initial soil strengths were in the range of 50-90kPa. Following treatment, test results indicated strengths in excess of 3MPa at 28 days, surpassing the target strength of 2MPa. Soil strengths were confirmed by taking core samples of the jet grout material and subjecting them to compression testing.
Working on a small site, our specialist plant and operators were required to complete the Super-jet grouting mpleted in difficult conditions.