ABSTRACT
Impact compaction trials were performed at Kriel on a residential site overlain by compressible windblown sands. The purpose of the trials was to assess the depth and degree of improvement attainable with various compactors of varying energy levels and included a vibratory compactor and four impact compactors. In addition, the trials had to indicate the most sensible ways of measuring the effectiveness of compaction.
Several in situ and laboratory tests were performed to characterise the in situ materials in terms of their salient engineering properties before and after compaction. The latter included sections that were subjected to 20, 40 and 60 passes of the compaction equipment.
The trials have indicated that on this site significant improvement of the soil was attained by the impact compactors to depths of 1,5 m as opposed to only about 0,3 m by the vibratory compactor. Tests which have proved worthwhile in characterising the virgin material and measuring the effectiveness of the compactive effort included level surveys; DCP tests; plate bearing tests, indicator tests, moisture content tests, oedometer tests and laboratory compaction tests. The specific value of some these tests are highlighted in terms of their ability to reflect different aspects of improvement during the compaction process.
