In some remote works area or when the bulky compaction work is to be carried out beyond 1200mm below formation level, the site supervisor could suggest to use a what we called the “ product specification ” to determine the relative compaction of the backfill.
To begin, we set out and agree with the Engineer Representative a trial compaction area and record the thickness of compacted layers, number of passes performed and the weight or model of compacting roller to achieve the required degree of compaction. After all these data are noted down and agreed, we shall then proceed the same process of work continuously and without taking Sand Replacement Tests and awaiting laboratory results for approval to the next layer. But bear in mind that the site supervisor should discuss in advance and agrees with the ER’s staff first or otherwise they may request for retrospective test(s) on layer which is already 1000mm below the current working level.