Anti-cracking and anti-floating fiber-reinforced synchronous grouting slurry for shield construction

Abstract

The invention belongs to the technical field of tunnel shield construction, and provides an anti-cracking and anti-floating fiber-reinforced synchronous grouting slurry for shield construction. The grouting slurry is made by mixing cement, medium coarse sand, a montmorillonite ore powder, water, sodium nitrite, a water reducing agent, and monofilament bundle fiber, wherein a mass ratio of water tothe cement is 1.2:1-1:1; a mass ratio of the cement to the medium coarse sand is 0.3:1-0.6:1; a mass ratio of the montmorillonite ore powder to the cement is 1:1; sodium nitrite is 3%-6% of the cement mass; the water reducing agent is 0.2%-2% of the cement mass; and the fiber blending content is 0.1%-0.5% of the cement mass. The bleeding rate is low, the slurry flow is constrained by the dispersed fiber, the consolidation shrinkage is small, the solidified body has good tensile strength, flexural strength, bending toughness, impermeability, durability and other properties, the floating risk of shield segments is effectively reduced, the occurrence of cracks in the grouting solidified body is reduced, and the construction cost is reduced.

Description

technical field [0001] The invention belongs to the technical field of tunnel shield construction, and in particular relates to a fiber-reinforced synchronous grouting grout for anti-cracking and anti-floating shield construction. Background technique [0002] When using the shield method to excavate subway tunnels, due to the existence of gaps in the tail of the shield, such gaps need to be filled by grouting. As the initial setting of the grout takes a long time, the tunnel shield machine has been driving forward. Therefore, the shield machine always has a certain length of segment structure in the incompletely solidified slurry. When the slurry flows downward, the segment will be displaced upward under the action of buoyancy. In the sandy soil layer with poor self-stability, after the grout injected behind the shield machine wall fills the gap at the tail of the shield, the grout will penetrate into the soil layer under the action of grouting pressure, which causes the ...

AI Technical Summary

Problems solved by technology

In the sandy soil layer with poor self-stability, after the grout injected behind the shield machine wall fills the gap at the tail of the shield, the grout will penetrate into the soil layer under the action of grouting pressure, which causes the loss of grouting pressure. This is also very easy to cause the tunnel segment to float up

When the floating amount of the segment exceeds a certain limit, it will cause the segment joints to open and stagger, and even cause the segment to be damaged

At the same time, the traditional grout has limited shear and tensile capabilities after solidification, and cracks are prone to occur and rapidly expand, causing water leakage and other diseases in the shield tunnel.

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