CONSTRUCTING METHOD OF LARGE-DEPTH SHAFT

PURPOSE:To construct a large-depth shaft, which has a bore of approximately 2m-6m and is sunk extending over an underground section of 50m-100m. CONSTITUTION:A reinforced concrete slab 3 is constructed at a place, where a shaft 11 is built, a cylindrical-shaped muddy water tank 5 for pressing is installed onto the slab 3, and a stage 10 for operation higher than the muddy water tank 5 for pressing is mounted. The shaft 11 is underwater-excavated up to desired depth by utilizing a bored-wall stabilizing liquid 12. A tubular body module 15, in which a lower bottom is sealed, is inserted into the shaft 11, and set up under the state, in which the module 15 is floated on a level by using buoyancy by the bored-wall stabilizing liquid 12. Movable load resisting buoyancy working to the tubular body module 15 is applied, and the sinking operation of the tubular body module 15 is promoted at every one module. The module 15 reaches desired depth, and a back-filling material is carried out into the clearance of the shaft 11 and tubular bodies 15, 15'. The large-depth shaft is built in a safer manner and with more excellent workability than a conventional technique, thus constructing the shaft at low cost in a short construction period.