Apparatus for forming a multi-walled trench

Abstract

A system for forming a multi-walled trench comprising a pair of frame members, each having a horizontal section and a section depending from the horizontal section; a holding pan having sidewalls exterior to the depending portion of the frame members, a bottom floor disposed between the sidewalls, and flanges on each sidewall extending parallel to the plane of the horizontal section of the frame member and away from the depending portion; an outer wall disposed within the holding pan having an inside surface and an outside surface, the outside surface of the outer wall engaging at least a portion of the sidewalls and the bottom walls of the holding pan; an inner wall disposed within the outer wall having an inside surface and an outside surface, the inside surface of the inner wall engaging at least a portion of the inner surface of the depending portion of the frame members, and a cavity being formed between the outside surface of the inner wall and the inside surface of the outer wall; means in the cavity for separating the inner wall from the outer wall to allow the expansion and contraction of each wall relative to the other; means for adjustably securing each frame member to a respective one of the flanges on a sidewall whereby the inner and outer walls are maintained in their desired locations within the pan; and adjustable anchoring means attached to the frame members for providing vertical adjustment of the frame members relative to the ground and to each other.