Soil response to surface impact loads during low energy dynamic compaction

Abstract

Low energy dynamic compaction has been developed as an efficient and rapid method of improving properties of foundation soils unsuitable for moderate building loads. A series of low energy dynamic compaction tests was undertaken on rigorously controlled model beds of sand at 1:20th scale in a 500 g tonne centrifuge at 20 g to prove the system and to validate an innovative real-time soil stiffness monitoring approach. The results of seven centrifuge tests are presented to demonstrate the effect of the impact on the performance of the sand bed with increasing number of blows. Attenuation monitored by the dynamic load cells and embedded accelerometers showed improvement of soil mechanical behaviour. The rate and efficiency of improvement was clearly demonstrated by the relationship of peak particle velocity and dynamic peak pressure with increasing number of blows. The soil response was monitored by real time signal processing and analysis using the WAK (Wave Activated Stiffness (K)) analysis which has been proved to be a very reliable indicator of process success. © 2009 Asian Network for Scientific Information.