METHOD OF LONG-SIZED FOREPOLING METHOD

摘要

PROBLEM TO BE SOLVED: To efficiently remove a forepoling steel pipe driven to a tunnel-face rear ground. SOLUTION: In the method of long-sized forepoling construction in which long-sized forepoling steel pipes in which a plurality of unit pipes are connected are driven at a fixed angle of elevationθfrom a tunnel axis at regular intervals along the arch circumferential direction of a tunnel on a ground in the interior section of a tunnel face 4, a continuous improved body is formed by injecting a grout to the peripheral ground of the forepoling steel pipes through grout discharge openings formed to the forepoling steep pipes and the ground in the interior section of the tunnel face 4 is reinforced precedently by the improved body, a resin pipe is used as a terminal pipe 10C in the unit pipes when the forepoling steel pipes are driven from the surface of the tunnel face 4 at a driving angle of elevationθ11, where a fixed range from the mouths of the forepoling steel pipes is left in a tunnel cross section.