| 摘要 |
PROBLEM TO BE SOLVED: To smoothen the transmission of a force in a connecting part by leaving the lining concrete opposite to a new tunnel of an existing tunnel as it is, and connecting the end part of a new main timbering structure to the end part of the residual lining concrete. SOLUTION: Each section of existing and new tunnels 1, 2 is formed in the oblique cross merging section of the side part of the existing tunnel 1 and the new tunnel 2. The lining concrete 25 on the existing tunnel 1 side of the flat semicircular tunnel section is left, and the end part 20a of a new main timbering structure is butted and connected to the end part 25a of the residual lining concrete 25. Therefore, the stress of the end part 20a of the steel timbering 20 is received by the peripheral bedrock reinforced by a spray concrete 12 through a member end force dispersing plate 16. The stress of the end part 10a of an existing steel timbering 10 is received by a new lining concrete 5 through a member end force dispersing plate 15. Thus, the new and existing tunnels can be safely and economically crossed and merged. |
