Ground-compacting system using explosive charges

摘要

The charge (4) can be delivered right to the end of the borehole and fired by igniter wires, these being retracted before a further charge is inserted. Alternatively a fuse cord can be used, or a delayed-action fuse. The borehole can be without an outlet, and it can be formed by a pilot drill bit and a coaxial flushing one, the pilot bit being extracted when drilling is complete and before insertion of the charge, while the flushing bit remains in the borehole. The charge used can be of pumpable material, and can be thrust home by a go-devil. A sealant can be provided on the hollow cylinder containing the charge between it and the internal surface of the drill bit.