Being laid out in the front part of the road widening type shielded tunnelling machine

摘要

PROBLEM TO BE SOLVED: To provide a widening type shield boring machine capable of efficiently excavating a widening cross section without causing any increase of propulsion resistance while preventing the collapse of a bedrock.;SOLUTION: In the widening type shield boring machine equipped with the first cutter head placed in the front section of a shield body 1 to excavate a standard cross section and the second cutter head 11 coming in and out from a drum section of the shield body 1 to excavate a widening cross section Tw, it is so constituted that a widening opening section 12 enabling the second cutter head 11 to freely coming in and out is formed in a skin plate 1a of the shield body 1, at the same time, a pressure holding chamber 13 communicated with the widening opening section 12 to store the second cutter head 11 is formed in the shield body 1, an opening and closing shutter device 14 having an opening and closing plate 27 enabling the widening opening section 12 to freely open and close is provided and that a sludge supply pipe 34 supplying a fluid to the pressure holding chamber 13 and a sludge removal pipe 35 removing excavated soil and sand together with the fluid are provided.;COPYRIGHT: (C)2006,JPO&NCIPI