A method apparatus, and product of forming consolidated earth columns of cement grout or mortar to be used, for instance, in building foundations. The method is designed to drastically reduce the time taken to form consolidation columns and to allow consolidation of earth particularly difficult to bore. The method consists of injecting the consolidating grout during the ascent of the drilling tool from the earth supplying air, at the same time, to the pneumatic percussion tool used to make the preliminary drilling.The plant to put the method into effect comprises a rotating joint manifold (6) at the upper end of the boring drill (11), equipped with tangentially arranged inlets, even inclined; an air manifold (15) to supply compressed air to the pneumatic percussion tool through the external annular chamber (28) of said boring drill (11); a grout distributor (36) equipped with ejection nozzles (38) the axes of which are inclined with respect to the axis of the drill. The column (46) is cylindrical in shape, with transversal projections (47).