Abstract:
ABSTRACT
Impact rolling is a ground improvement technique used to reduce compressibility and enhance the bearing capacity of soils, particularly in shallow foundation applications. This paper presents a case study of a geotechnical investigation carried out at a commercial development site in Marion, South Australia, where impact rolling was employed to improve the soil conditions for shallow footings. The site was underlain by a combination of fill material, soft to firm sandy/silty clay, and granular lenses. The objective was to assess the effectiveness of impact rolling, particularly on cohesive materials, and to determine the improvement in bearing capacity, subgrade stiffness and settlement control.
Pre- and post-treatment testing, including Cone Penetration Testing (CPT) and Dynamic Cone Penetrometer (DCP), was conducted to evaluate soil conditions before and after treatment. The results demonstrated that impact rolling improved the soil in granular zones, reducing settlement by up to 200 mm. However, in cohesive materials, such as clay and silt, the treatment exhibited a much lower degree of effectiveness. The study concludes that while impact rolling is a viable method for improving ground conditions in certain soil types, its effectiveness is less reliable in fine-grained soils and may require supplementary measures for areas with poor responsiveness.
Keywords: impact rolling, ground improvement, shallow foundations, geotechnical investigation, cohesive materials