SHIELD MACHINE AND SHIELD TUNNELING METHOD

摘要

PROBLEM TO BE SOLVED: To provide shield technique capable of cutting an anchor due to the rotation of a cutter head which is not caught by the anchor. SOLUTION: In this shield machine, a plurality of cutting bits 7 of roller bit type which are provided with many cutout parts on outer periphery and have a blade width which is substantially a half or less of an ordinary roller bit are attached to an outer peripheral ring 4 and are arranged so as to cut an outer peripheral side of a digging cross section precedently. A plurality of preceding bits 8 which are 1/3 or less of a blade width of a main cutter bit 9 cutting a working face by preceding the main cutter bit 9 are attached to a spoke 3 so that they can cut the inner peripheral side of a digging cross section more than a cutting bit 7 and are arranged in such a way that a tip of a blade tip of preceding bit 8 becomes lower toward the outer peripheral side. Then, an underground radar 6 for detecting an anchor 21 is attached to the spoke 3. When the underground radar 6 detects the anchor 21, a propulsion speed of the shield machine is reduced down to a proper speed for cutting the anchor 21 to cut the anchor 21 by the bits 7, 8.