| 摘要 |
PROBLEM TO BE SOLVED: To provide a tunnel excavating method which dispenses with special heavyweight steel even in the excavation of an extra-large cross-section tunnel, and enhances workability of timbering formation. SOLUTION: A drift corresponding to the side part of the tunnel is excavated (S21); timbering for supporting natural ground and mid-wall timbering are formed outside and inside the drift; and horizontal timbering, by which the drift is split into two upper and lower parts, is formed between the timbering for supporting the natural ground and the mid-wall timbering (S22-S24). Next, lining concrete is formed on the timbering for supporting the natural ground in the drift (S25); a lower half part of an in-drift space is backfilled with soil (S26); and an upper half part of the natural ground between the drifts is excavated so that the timbering for supporting the natural ground and the horizontal timbering can be formed on the top surface and bottom surface of a space between the drifts (S27). After that, concrete is placed on the timbering for the supporting the natural ground so that the lining concrete can be formed part by part, while an exposed part of the mid-wall timbering is removed part by part (S28). Subsequently, the natural ground on the downside of the horizontal timbering and the backfilled soil are excavated (S29) and a remaining part of the mid-wall timbering and the horizontal timbering is removed (S30). COPYRIGHT: (C)2004,JPO
|
