A mandrel for forming a cavity at a target location. The mandrel includes a base part positioned at a top end of the mandrel, a first middle part, a second middle part, a third middle part, a first plurality of diamond-shaped crushing blades, a second plurality of diamond-shaped crushing blades, and a bore head positioned at a bottom end of the mandrel. The first plurality of diamond-shaped crushing blades are attached around the first middle part and the second middle part. The second plurality of diamond-shaped crushing blades are attached around the third middle part and the bore head.