Sustainable Solution to Expansive Subgrade and Existing Pavement Using Geoconfinement System

Abstract

The Darling Downs region, located over 100 km west of Brisbane, comprises predominately fertile black soil. Black soil found across the region has characteristics that are extremely problematic to civil engineers and have caused significant damage to the road infrastructure in the region. The black soil in the region has a high shrink/ swell characteristic which has caused substantial pavement damage through rutting, shoving, washouts and settlement issues. Many pavement rehabilitation techniques, such as lime stabilization and foamed bitumen, have been used to minimize the damage caused by moisture infiltration. However, the issues remain. The Department of Transport and Main Roads developed ten innovative rehabilitation methods as a trial using geocells and geosynthetics along a 1km section of the main highway in the region. The Gore Highway had been identified as the ideal location as previous rehabilitation methods achieved limited benefits in reducing pavement failures, which posed safety concerns.