Shield synchronization slip casting construction technology

Abstract

The invention discloses a shield synchronization slip casting construction technology, comprising the following steps: A) stirring the slip casting material into single grout via a grout mix and feeding system of a mixing station; B) conveying the mixed single grout to shield grout groove through a transportation system; and C) conducting synchronous slip casting to tailskin building interspaces through a shield slip casting system; wherein, in step A), the initial slump is 9-14cm, the sand factor is 50-60%, the specific gravity is not less than 1.9kg / L, the bleeding rate is not more than 5%, the anti-cutting yield strength 8h is more than or equal to 800Pa and the later-stage solid shrinkage is not more than 1%; in step C), the slip casting pressure P=P1+P2, wherein, P1 is a water-soil pressure value around the slip casting point and P2 is pressure loss of the slip casting pipe. The grout in the invention has the advantages of higher anti-cutting yield strength, long service time, no occurrence of eduction and pipe blocking and good peaceability and the like. The invention further has the advantages of low production cost of grout, low slip casting rate, low slip casting volume, no need of secondary supplement slip casting, controllable distortion and settlement of completed ground surface and high quality of tunnel circular forming.

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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