What is it about?

Rolling Dynamic Compaction (RDC) imparts energy to the ground via the use of a heavy non-circular module that impacts the ground. To quantify the effects of RDC, testing is typically undertaken pre- and/or post-compaction to determine if a project specification has been met (or otherwise). However, such testing methods fail to capture the dynamic effects of a single module impact. This study involved conducting a full-scale research trial where an 8-tonne 4-sided impact roller (shown in Figure 1) compacted homogeneous fill material in which buried earth pressure cells and accelerometers were placed at a depth of 0.7 m to capture the real-time ground response to RDC beneath the surface.

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Why is it important?

Key findings or contributions to knowledge from this paper include: • Pressures up to 1100 kPa were measured at a depth of 0.7 m below the ground surface. • Quantified that the dynamic loading and unloading of soil occurs over a duration of approximately 0.05 seconds. • The acceleration response due to impact was measured in three orthogonal directions with vertical accelerations dominant (peak accelerations up to 21g were measured). • The accelerometer response indicated that the direction of travel of the roller influences the ground response; an expected result given the module is not just falling vertically onto the ground. • Uneven module geometry results in some passes imparting much greater pressures than others. This was quantified by measuring the force-displacement response for consecutive passes. • Force was quantified from measurements of the pressure imparted into the soil using buried earth pressure cells of known cross-sectional area. Displacement was inferred from double-integration of the accelerometer data, and quantified both recoverable (elastic) and permanent (plastic) components of soil settlement.


This paper captures the in-ground response using bespoke instrumentation in homogeneous soil. The change in vertical stress due to rolling dynamic compaction was measured using an earth pressure cell and the acceleration response determined in three orthogonal directions. Rather than rely on testing methods that are undertaken pre- and/or post-compaction, this paper quantified the dynamic behaviour of the soil beneath the ground surface in real-time, enabling the loading and unloading of the soil to be quantified for single and multiple module impacts.

Dr Brendan T Scott
University of Adelaide

Read the Original

This page is a summary of: Ground response to rolling dynamic compaction, Géotechnique Letters, June 2019, ICE Publishing, DOI: 10.1680/jgele.18.00208.
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