| 摘要 |
PROBLEM TO BE SOLVED: To restrain blocking-up in an earth removing pipe when excavated earth and sand are fluidity carried, and restrain an increase in cutter torque by filling a working face surface with water and muddy water, and excavating the ground while injecting a dispersant into the vicinity of a cutter. SOLUTION: In a muddy water pressurizing shielding construction method to construct and create a tunnel, a working face surface is filed with water or muddy water, and the ground is excavated while injecting a dispersant into the vicinity of a cutter. Excavated earth and sand are fluidly carried as an earth removing liquid from an earth removing pipe, and the tunnel is constructed and created. Alkaline metal salt of a silicic acid, a metasilicic acid, a phosphoric acid, a polyphosphoric acid and a hexametaphosphoric acid and a hydroxide of alkaline metal are used as the dispersant. An adding quantity of the dispersant is added in the quantity ratio not less than 0.5 pts.wt. per water or muddy water 100 pts.wt. |
