Paul Pfister. This paper was first published in GE’s April 1985 edition.
Several soil improvement methods require the drilling of a large number of holes; this is the case for soil or rock grouting, as well as ground freezing. Uncored holes are usually drilled in connection with these methods. Over the past years, the contractor’s concern has always been to optimise drilling methods in order to increase the drill’s output, to minimise drilling hazards, and to reduce costs. This concern has led to an extremely large variety of drilling techniques, tools and types of drilling machines.