Quantifying the zone of influence of the impact roller

Abstract

Rolling dynamic compaction (RDC) involves traversing the ground by means of a non-circular module consisting of 3, 4 or 5 sides. Over the last few decades, a number of studies have been carried out in an effort to quantify the effectiveness of RDC. In this study, the zone of influence of the 4-sided ‘impact roller’ was measured in a systematic fashion in the field by means of a series of earth pressure cells (EPCs) embedded in the ground, in situ density measurements and dynamic cone penetration tests. Measurements obtained from the field trial, which was conducted at an open-cut mine in South Australia, suggest that the depth of influence for which there is significant and quantifiable improvement with the roller is approximately 2.1 m below the ground surface and this corresponded to soil stress readings of between 150 and 200 kPa. Positive pressure readings due to RDC were also measured by the EPCs buried up to 3.85 m below the ground surface, indicating that the actual zone of influence (for which there is improvement) extends beyond this depth.