Impact compaction on a subgrade layer overlying deep deposit

Abstract

Recent expansions of urban communities around the world have forced geotechnical engineers to deal with weak deep deposit for the construction of highways and roads. The current practice in estimating the level of field compaction is based on the results of a laboratory test, known as ‘Proctor’, where wide discrepancies are found between the laboratory-predicted and the field measurements. Impact compaction is a widespread soil-improvement technique that has been used with proven effectiveness. The technique is environmentally friendly, simple to apply and relatively inexpensive. This study presents a numerical model, which was developed to simulate the case of a dry thin subgrade layer overlying a deep deposit and subjected to impact compaction. The model is capable of measuring the total energy applied to the surface of the subgrade layer and its two components; namely the portion dissipated into the lower deposit and the portion remaining in the subgrade layer causing its compaction. A design guideline is presented.

Keywords::

• impact load
• soil compaction
• boundary conditions
• numerical modelling
• geotechnical engineering
• pavement design

Acknowledgements

The financial support from the Natural Science and Engineering Research Council of Canada (NSERC) and Concordia University are acknowledged.