Compaction of fills in land reclamation by rapid impact

It is necessary to apply high levels of energy to fill materials, using heavy compaction plant with material placed in thin layers, to achieve performance that is compatible with most development specifications. Site geometry or programme constraints often render this traditional approach inappropriate. A technique originally developed for military use and hitherto applied in a limited range of civil projects in the UK has been adopted internationally for a much wider range of materials and applications. The rapid impact compactor has been used to successfully compact a wide range of both placed and in situ granular materials, including rockfills, as well as to stabilise naturally occurring loess sand and silt deposits in seismic zones. A brief explanation of the technique is followed by a number of case histories from around the world, in which the design, execution and verification of compaction are presented. As with any compaction, quality control is of paramount importance, and in-built process controls and typical field testing are described. The advantages of this technique for thicker layer compaction and discrete small area compaction are highlighted.