Derek Avalle

BSc(Eng) MSc(Eng) GDE PGCE
Postgraduate Research Student
Centre for Geotechnical Research
www.broons.com

School of Civil Engineering
Phone: +61 2 9918 0788
Fax: +61 2 9918 0955
Email: derek@broons.com

Research project - The Impact Roller

Supervisor: Prof John Small
Associate Supervisor: Prof John Carter

Impact rollers consist of non-circular modules that are pulled along, rotate due to the frictional force on the ground surface and dynamically compact the ground. An example is the Broons BH-1300 “Square” Impact Roller with a 4-sided 8t module (see picture), which is towed at 10-12km/h. The technology is sometimes known as “rolling dynamic compaction”. The key feature of impact rollers is that they provide deep layer compaction, having a significantly greater depth of influence than conventional rollers, and they travel much faster, thus offering a substantial productivity gain.

Over the last 20 years, since impact rolling was introduced into Australia and the technology was made available internationally, impact rollers have found a place on the practical side of ground improvement in various sectors and they have been used on several hundred projects around Australia and in many other countries.

There is, however, a lack of available scientific research information, or professional or industry guidance in relation to impact rolling, which has resulted in geotechnical engineers and designers having to rely on product marketing documents and reported project experience. Specifications for impact rolling vary widely, as do the protocols adopted for monitoring, testing and verification.

The research will focus on a geotechnical model that describes an understanding of the processes during ground improvement using an impact roller. The response of the ground to the impact from a non-circular compaction module travelling at speed, and the module’s effectiveness with differing soil types and ground conditions will form the central basis for the research effort.

Selected publications

Bouazza, A., and Avalle, D.L. (2006) "Verification of the Effects of Rolling Dynamic Compaction using a Continuous Surface Wave System," Australian Geomechanics, (submitted).
Bouazza, A., and Avalle, D.L. (2006) "Effectiveness of Rolling Dynamic Compaction on an Old Waste Tip," ISSMGE 5th Int. Congress on Environmental Geotechnics, Cardiff, (accepted).
Avalle, D.L. and McKenzie, R.W. (2005) "Ground Improvement of Landfill Site using the "Square" Impact Roller," Australian Geomechanics, Vol. 40, No. 4, pp. 15-21.
Avalle, D.L. and Carter, J.P. (2005) "Evaluating the improvement from impact rolling on sand," 6th Int. Conf. on Ground Improvement Techniques, Coimbra, Portugal, pp. 153-160.
Avalle, D.L. (2004) "Impact Rolling in the Spectrum of Compaction Techniques and Equipment," Australian Geomechanics Earthworks Seminar, Adelaide.
Avalle, D.L. (2004) "A Note on Specifications for the Use of the Impact Roller for Earthworks," Australian Geomechanics Earthworks Seminar, Adelaide.
Avalle, D.L. and Young, G. (2004) "Trial Programme and Recent Use of the Impact Roller in Sydney," Australian Geomechanics Earthworks Seminar, Adelaide.
Avalle, D. and Grounds, R. (2004) "Improving Pavement Subgrade with the 'Square' Impact Roller," 23rd Annual Southern African Transport Conference, Pretoria, pp. 44-54.
Avalle, D.L. (2004) "Ground improvement using the "square" Impact Roller - case studies," 5th International Conference on Ground Improvement Techniques, Kuala Lumpur, pp. 101-108.
Avalle, D.L. (2004) "Use of the Impact Roller to Reduce Agricultural Water Loss," 9th ANZ Conference on Geomechanics, Auckland, pp. 513-518.

The Impact Roller in action