Shield synchronous grouting construction technology

Abstract

The invention discloses a shield synchronous grouting construction process, comprising the following steps: A) mixing grouting materials into a single slurry in a slurry mixing and feeding system of a mixing station; B) transporting the mixed single slurry through a transportation system into the shield grout storage tank; C) the shield grouting system performs synchronous grouting to the shield tail building gap; wherein the initial slump of the grout in step A) is 9-14cm, and the sand content is 50-60%. Specific gravity ≥ 1.9kg / L, bleeding rate ≤ 5%, shear yield strength 8h ≥ 800pa, post-concrete shrinkage rate ≤ 1%; grouting pressure in step C) P=P1+P2, where P1 is the injection pressure The water and soil pressure value around the grout point, P2 is the pressure loss of the grouting pipe. In the shield synchronous grouting construction technology of the present invention, the grout has the advantages of high shear yield strength, long service life, no segregation and pipe plugging, good workability, and the like. In the process of the invention, the grout production cost is low, the grouting rate is small, the grouting amount is low, no secondary supplementary grouting is needed, the deformation and settlement of the ground surface after construction are easy to control, and the ring-forming quality of the tunnel is high.

Description

technical field [0001] The invention belongs to the field of tunnel construction, in particular to a shield synchronous grouting construction technology. Background technique [0002] During the excavation construction of subway tunnels (shield diameter 6-6.5m) using the shield method, synchronous grouting is the main means to fill the construction gap between the soil and the segment ring and reduce the later deformation, and it is also the main method for shield tunneling. An important process in construction. During the shield tunneling construction, it is required that the grouting should be injected in a timely, uniform and sufficient amount to ensure that the building voids are filled in a timely and sufficient amount, and thereby minimize the surface deformation and segment offset. [0003] In order to meet the above requirements, three different synchronous grouting construction techniques are commonly used in the current shield tunneling construction of subway tunn...

AI Technical Summary

Problems solved by technology

Although hardenable cement single-slurry can make the slurry around the segment form a relatively dense compact body, in the actual construction process, the slurry can be used for a short time, the slurry is easy to segregate and block the pipe, the construction is inconvenient, and the slurry is thin and grouted. It is mainly used in hard rock formations with good self-supporting.

The two-liquid grouting method of mixing cement slurry and water glass has the advantages of short slurry setting time, high slurry solid strength, certain anti-seepage and anti-seepage effects, and can better control the initial settlement and stability of the tunnel. However, there are the following deficiencies in the use of double-liquid synchronous grouting construction in China: ① easy to block, high requirements for operation control; ② the amount of grouting is about 180-250% of the theoretical value, and the cost of grouting is high; Cause surface subsidence, usually using secondary grouting

However, in the construction of subway tunnels, due to the site conditions and the limitation of the shield construction space, many problems occurred in the application of the synchronous grouting slurry, and the corresponding synchronous grouting construction technology could not be realized, such as the insufficient capacity of the ground grouting equipment, Inaccurate feeding during slurry preparation, high labor intensity, difficult slurry quality control, poor workability, low efficiency during transportation, easy blockage, frequent blockage during shield grouting, insufficient grouting efficiency, etc.

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