SMALL-BORE PIPELINE EXCAVATING CONSTRUCTION METHOD AND PIPELINE EXCAVATING DEVICE

PROBLEM TO BE SOLVED: To provide a small-bore pipeline excavating construction method and an excavating device for excavating a small bore pipeline simultaneously with laying buried pipes, dispensing with an arrival side shaft and maintaining equipment equipped at a lead pipe such as replacing a cutter even in the middle of excavation. SOLUTION: At least the retreat time diameter of a lead pipe 1 is set to be equal to or smaller than the inner diameters of buried pipes 25-1-25-n, and the guide pipe 1 is retreated inside the buried pipes 25-1-25-n after the completion of laying the required number of buried pipes 25-1-25-n laid simultaneously with excavation. At this retreat time, a filler is discharged from an excavated sediment discharge space part of a screw conveyor 6 to the periphery of a cutter head 8 through a clearance of the cutter head 8 toward outbreak space formed in front of the front buried pipe 25-1, and the filler is filled in the outbreak space. After the filler is filled in the outbreak space, discharge of the filler is stopped, and the retreat of the lead pipe 1 is continued and led back to the start shaft.