Franz's Trail, Whistler, B.C. Canada
A Rapid Impact Compactor is shown above densifying an area filled with loose sands and gravels (with some silt and wood fragments) in the area of a future parkade, or "parking structure". The on-board computer was on a set of 3mm. The original compaction pass was on a 20-foot spacing, followed by a second pass at the intermediate impact points. The number of blows varied from 40 to 65 on the first pass, with the count dropping to 20 to 35 on the secondary pass. Depth of penetration per location averaged about 12 to 18 inches. The test results allowed the owner to use RIC to densify the subgrade in-situ, saving a substantial amount of time and money over the alternative of subexcavation, recompaction, and casting of a raft foundation.
The following is a graph of comparative Becker penetration test results, showing significant improvement in the post-treatment profile: