Method and apparatus of completing slurry shield tunneling at vertical

Abstract

A method of completing a tunnel excavation with a slurry shield type tunneling machine through a soft ground having a high water content or much gushing water, advancing the machine from the ground into a vertical shaft at, for example, a tunnel terminating point while preventing any ground collapse or gushing water at a vertical shaft wall finally excavated, and an apparatus for performing the method. A substantially ring-shaped liquid-tight packing means having an inner diameter large enough for passing therethrough the machine while maintaining a liquid-tight sealing around the outer periphery of the machine is provided at a position of a final tunnel port on a shaft wall at which the machine reaches the vertical shaft and along the inside surface of sheet piles struck in advance on the vertical shaft wall, a pressurized liquid chamber having substantially the same diameter as that of the packing means is formed in the vertical shaft so as to open on the packing means side, the liquid pressure in said chamber is kept at least as high as ground water pressure or ground pressure, the sheet pile is removed from the final port position, and the machine is then propelled to pass through the remaining ground layer and packing means and is receptacled in the pressure chamber. After back-filling around the final port is completed, the chamber and machine are removed.