| 摘要 |
PROBLEM TO BE SOLVED: To enable cutting the covering of an existing tunnel, while maintaining its stability or balanced conditions, and water stop to be done easily and completely, after the completion of the cutting work, without any flood within the tunnel. SOLUTION: A shield machine 12 having a rotary cutter ring 14 with a cutting bit equipped at its leading end is used to excavate a new tunnel 11 crossing an existing tunnel 10. At the time when the cutter ring 14 at a position close to the existing tunnel 10 is advanced to cut the covering of the existing tunnel and open a penetration hole, a filling layer 16 made of concrete or the like is formed beforehand in such a thickness that the leading end of the layer 16 may not protrude in the existing tunnel 10 inside the tunnel at a position where a new tunnel is connected with the existing tunnel. The filling layer 16 is formed after the completion of cutting work by the cutter ring 14. After the covering 10a of existing tunnel 10 is cut with the cutter ring 14, part of the filling layer 16 located within the cutting ring is removed to open the penetration hole. COPYRIGHT: (C)2005,JPO&NCIPI
|
