| 摘要 |
PROBLEM TO BE SOLVED: To provide a tunnel construction method capable of improving the period of construction work, costs and safety when constructing a large tunnel with the section contracted by using the Multi-Micro Shield Tunnel Method. SOLUTION: According to this tunnel construction method, a plurality of tunnels 1 each having a small rectangular section are formed at predetermined intervals, then each tunnel 1c with a small section is formed for a predetermined distance by a gathering machine with a plurality of drive machines bundled, a drive machine is started from the gathering machine to the tunnel 1c with the small section and a tunnel 19 with a further smaller diameter is formed continuously, the small-diameter tunnel 1c and the further small-diameter tunnel 19 are located adjacently, another small-diameter tunnel 1a is formed with a slope along the tunnels stated above, side portions of these tunnels 1a, 1c, 19, 1b, 1 are connected together and the section of the large-diameter tunnel is contracted. Then, the gaps among the tunnels 1a, 1c, 19, 1b and 1 are made narrower, so that the period of timbering work, costs and safety for connecting them can be improved. Also, part of the drive machines can be reused thereby improving the economy. |
