Method and apparatus for installation of an outer-cased piling

A method for installing a structural support piling in a subsoil setting passing through a zone of contamination comprising:

• a. creating a borehole through said contaminated ground to a depth below the zone of contamination and ending adjacent thereto forming a substantially cylindrical cavity surrounded by substantially cylindrical walls and a closed bottom,
• b. placing in the so formed borehole and extending past the contaminated zone a cylindrical metal casing having an upper and a lower end and an inside surface, the upper end being capable of being closed by an attachable cap, the lower end being open;
• c. closing the upper end of the metal casing by attaching an attachable cap thereto, the cap having an aperture therethrough, and sealingly inserting a tube through the aperture of the cap, the tube being connected to a source of pumpable cementitious material, said tube extending substantially to the bottom of said borehole and the source including a pumping device;
• d. pumping an amount of the pumpable cementitious material through said tube into the space formed by the bottom of said borehole and said inside surface of said casing to a depth substantially sufficient to form an hydraulic seal at the lower end of the casing;
• e. while the cementitious material is yet fluid, filling said casing with water from the topmost portion of said hydraulic seal to at least a level in the upper portion of said casing or adjacent to the upper end of said casing;
• f. pumping said cementitious material from said pumping device through said tube into said water-containing casing to the lower end thereof in a sufficient amount and under sufficient pressure so as to fill the annular space formed between said casing and the walls of said borehole with said cementitious material;
• g. allowing said cementitious material to cure to a hardened state to support said casing in a generally upright position;
• h. inserting a substantially cylindrical metal pile form with a closed bottom end through, and driving the pile form beyond, the bore of said casing and in substantial axial alignment therewith, the pile form being driven to a depth in the subsoil sufficient to provide support for a structure at or above ground level, said pile form not extending into any aquifer and forming an annular space between the outer wall of said metal pile form and the inner wall of said casing;
• i. filling said metal pile form with a pumpable structurally supporting cementitious material and allowing said structurally supporting cementitious material to cure, thus forming a structural support piling;
• and
• j. filling said annular space between the metal pile form and said casing with a pumpable cementitious material and allowing curing of said cementitious material to a hardened state.