摘要 |
A drill assembly for forming in ground granular columns without the need for vibratory compaction, said drill assembly includes a first drill (10) and a second drill (11), where the first drill is a tube (7), and the second drill includes a drill flight (26), wherein said first and second drills are concentric, and the second drill (11) is configured to lie at least partially within the first drill (10); such that the drill assembly is configured to form the granular column with primarily vertical compaction; when the drill assembly arrives at the required depth, the second drill (11) is used to feed an aggregate to a lower terminal end of the drill assembly, thus forming the granular column as the drill assembly is withdrawn. |