EXCAVATING METHOD FOR LARGE DIAMETER TUNNEL

摘要

PURPOSE:To provide an elliptical section having an expanded diameter by inclining a cutter drum when an advancing drift having a small diameter is excavated by means of a pilot excavation machine and then a tunnel having an expanded diameter is formed following the advancing drift by means of a reaming excavation machine provided at the rear of the advancing excavation machine. CONSTITUTION:A cutter head 22 of large diameter of a reaming excavation machine B is telescopically mounted to a drive cylinder 20 so as to be inclined with respect to the cylinder and only the outer periphery having expanded ring-shape provided with an excavation cutter is rotated by a hydraulic motor 21. A front supporter gripper is raised and front and rear grippers 28 are made contact with a drift wall 7 to generate reaction forces so that the cylinder 20 is contracted by the reaction forces, thereby pulling the cutter head 22, while the ground 7 around an advancing drift 1 is excavated by means of a pilot excavation machine A, whereby an elliptical shape having the major axis in the horizontal direction is formed. By changing the angle of inclination of the cutter 22 during excavation, a tunnel having peculiar elliptical section can be formed.