SHIELD MACHINE FOR PARTIAL HARD GROUND, METHOD FOR EXCAVATING PARTIAL HARD GROUND AND TUNNEL CONSTRUCTION METHOD FOR PARTIAL HARD GROUND

摘要

PROBLEM TO BE SOLVED: To provide a shield machine for a partial hard ground capable of realizing a stable pipe-jacking even when there is a hard ground in a part of a facing.;SOLUTION: In the shield machine 1 for the partial hard ground pipe-jacking a ground 7, in which there are a hard ground section 5 and a normal ground section 6 in the longitudinal direction, and cutting the facing 3 in which the hard ground section 5 and the normal ground section 6 are mixed, a rotary cutter 4 is installed to the front section of a shield machine body 2 while being opposed to the facing 3, a surface on the facing side of the cutter 4 is divided supposedly into a region X, in which only the normal ground section 6 is excavated, and a region Y, in which the normal ground section 6 and the hard ground section 5 are excavated, while being partitioned by a concentric circle centering around the center of rotation of the cutter, and a plurality of bits 18 for the hard ground are arranged so that at least one is brought into contact with the hard ground section 5 at all times during the rotation of the cutter 4 in the region Y in which the normal ground section 6 and the hard ground section 5 are excavated.;COPYRIGHT: (C)2004,JPO