ADDITIVE FOR DRILLING USING EARTH PRESSURE TYPE SHIELD CONSTRUCTION METHOD AND EARTH PRESSURE TYPE CONSTRUCTION METHOD

摘要

PURPOSE:To enlarge the applications area of an earth pressure type shield construction method by injecting a drilling additive into earth obtained by drilling and taken into the chamber of a shield machine, and discharging the earth, the additive being formed by addition of a fine fibrous material to a viscous material. CONSTITUTION:A shield machine comprises a face plate type cutter 1, a chamber 2, an earth discharging mechanism 4, an additive injection pipe 5, a screw conveyor 6 and a belt conveyor 8. Earth obtained by drilling is taken into the chamber 2 by rotation of the cutter 1 and an additive for drilling is injected and stirred. The additive is formed by addition of a fine fibrous material such as a paper-forming sludge and the like to a viscous material such as clay and the like. When mixed earth is discharged backward by the conveyor 6 sediment is converted by the effects of combination and screening of the sludge to such viscosity that the sediment is not washed away by hydraulic pressure. Thereby earth is stably discharged and the injection phenomenon of earth obtained by drilling can be avoided.