Ground improvement of landfill site using ‘square’ impact roller

One third of a 2.2 ha residential development site at Greensborough, Victoria, overlies an old refuse tip. The challenge for the development team was to engineer the site to a condition suitable for the proposed dwellings, maintaining a control on costs and achieving the specified environmental standards. After stripping the existing clay capping, leaving a thin cover over the waste, the site was subjected to ground improvement with the Broons BH-1300 “square” Impact Roller. Impact rolling continued until settlements became insignificant. Then a continuous capping was reinstated and the area surcharged. The suite of testing included settlement monitoring, intrusive and non-intrusive geotechnical tests before and after impact rolling, and vibration monitoring along the boundary with neighbouring houses. Ground improvement in this manner resulted in a cost-effective and environmentally sustainable solution.