Abstract: A structural assembly and a method are disclosed for an improved foundation element post-grouting technique incorporating a piston arrangement that consists of a barrel at the base of a pier or pile. Grout is pumped into the barrel via one or more conduits and the pressure from the grout exerts downward pressure on the barrel forcing it into the geomaterial below the foundation element and increasing the load bearing capacity of the foundation element. This assembly and method functions to contain the grout within the target grout area beneath the foundation element while simultaneously providing a means for measuring the strength of the geomaterial below the foundation element and the strain and movement associated with the geomaterial and the pier or pile.