Anti-blocking and anti-floating grouting material for shield tunnel synchronous grouting

Abstract

The invention discloses an anti-blocking and anti-floating grouting material for shield tunnel synchronous grouting, which comprises the following components: water, cement, water glass and a retarder, and is characterized in that the cement is 42.5-grade Portland cement; wherein the water glass is a sodium silicate aqueous solution with a baume degree of 30-40 degrees and a modulus of 3.1-3.3, and the retarder is an ammonium dihydrogen phosphate crystal with a purity of 99.0% or more, a pH value of 4.0-4.5 and a clarity of 3 or less. The grouting material not only has good anti-floating performance, but also can be used for quickly gelatinizing and eliminating buoyancy borne by the duct piece, so that the anti-floating requirement of the shield tunnel is met; the anti-blocking performanceis good, the situation that the grouting pipe is blocked due to the fact that slurry is gelled in the grouting pipe is avoided, and the construction efficiency is high; and meanwhile, the strength ofstones formed by grouting is high, so that the shield tunnel structure is more stable and reliable.

Description

technical field [0001] The invention relates to a grouting material for synchronous grouting of a shield tunnel. [0002] technical background [0003] In tunnel construction projects, the shield tunneling method has been widely used due to its advantages of high efficiency, safety, environmental protection, and little impact on ground traffic. During the excavation process of the shield tunnel, the segments are spliced ​​at the shield tail of the shield machine to form a segment ring. As the shield machine advances, the segment ring will break away from the shield tail and enter the soil; The diameter of the excavation is larger than the outer diameter of the segment ring, and there will be a ring-shaped shield gap with a thickness of 10-18cm between the segment (ring) detached from the shield tail and the soil; it needs to be uninterrupted during the advancement of the shield machine. Grouting should be done directly from the tail of the shield to the rear wall to fill the...

AI Technical Summary

Problems solved by technology

The single-liquid slurry uses cement as the main cementing material, and also includes river sand, bentonite and other materials, and its setting time is usually longer; although the gelling time can be shortened by adding an accelerator, its effect is limited. Generally, the physical gelation time cannot be shortened to the anti-floating time (30 minutes) required by the tunnel synchronous grouting, which will lead to the problem of floating of the shield lining structure; and blindly increasing the amount of accelerator will also cause gel formation. The problem of insufficient strength of the stone body in the later stage

The double-liquid slurry is mainly cement-sodium silicate double-liquid slurry, whose physical gelation time can meet the anti-floating requirements of synchronous grouting in tunnels, and can eliminate the buoyancy generated by the slurry after the segment comes out of the tail of the shield and before it floats up ; but its chemical gelation time is too short, which can be as short as ten seconds, which can easily cause blockage of the grouting pipe, and then need to stop the machine to clean the grouting pipe, resulting in low construction efficiency, discontinuous grouting, and poor grouting quality

And the strength of the stones formed in the later period is not high enough, which seriously restricts the application of cement-sodium silicate double liquid slurry in actual engineering

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