Method for producing bore holes for piling has a rock cutting hammer and concrete supply duct incorporated into a multi purpose boring head

摘要

A method for producing bore holes for concrete piling has a screw cutting drill with a central duct containing a concrete supply duct (4) and a compressed air feed for one or more rock cutting hammers (12). The drill prepares the bore hole and produces the piling without separate operations to line the hole and insert the concrete. In operation the rock cutting hammer head extends a short way below the cutting teeth (15) of the screw, to minimise the shear force on the cutting heads during the rotation of the screw. The prepared hole is backfilled with concrete as the drill is withdrawn.