Is there any experience with compaction by means of blasting of hydraulically placed calcareous (shelly) sands. It seems to be in general a very cost effective method, but i cannot find any literature on the subject in calcareous sands.
Blast compaction is efficient if the confining pressure is high (i.e. at larger depth), as the compaction effect depends on the reconsolidation of the soil layer after disturbance. The maximum degree of compaction that can be achieved is therefore limited.
My experience is that calcareous sands are difficult to compact, but more so difficult to test. CPT cone data usually show lower resistance values due to the crushing of the shells, even when in a dense state of compaction.
An important question is the purpose of compaction (liquefaction mitigation, settlement reduction, homogeneity etc). In many cases, the compaction requirements are unrealistically high and are set without understanding the effect of the compaction process.