| 摘要 |
PROBLEM TO BE SOLVED: To efficiently and integrally withdraw both large and small diameteral shield excavators through a pipeline of a tunnel to the side of the large diametral shield excavator, after joining, at a predetermined position in the ground, the two shield excavators excavating the tunnel from opposite directions. SOLUTION: The tunnel is excavated from the opposite directions while constructing a pipeline until the excavators are faced each other at the predetermined position. Then, a cutter head of the large diametral shield excavator is contracted and an inner cylindrical body provided with the cutter head is housed in an outer cylindrical body. The small diametral shield excavator is advanced and its outer cylindrical body is joined to the outer cylindrical body of the large diametral shield excavator to be unified. While the ground between the two shield excavators is excavated by the cutter head of the small diametral shield excavator, the inner cylindrical body provided with the cutter head is inserted into the outer cylindrical body of the large diametral shield excavator. After both of the cutter heads are joined to each other, the shield excavators are withdrawn through a large diametral pipeline leaving the outer cylindrical body behind. COPYRIGHT: (C)2005,JPO&NCIPI |
