Open-cut cast-in-place tunnel main body structure concrete anti-crack construction method

A technology for the main structure and construction method, which is applied in the direction of basic structure engineering, underwater structures, artificial islands, etc., can solve the problems of shrinkage and cracking of concrete that have not been completely solved, and achieve the purpose of suppressing penetrating shrinkage cracks, solving leakage problems, and improving construction efficiency. simple effect

CN113774957AActive Publication Date: 2021-12-10JIANGSU RES INST OF BUILDING SCI +3
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
Publication Date
2021-12-10

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Abstract

The invention belongs to the technical field of tunnel construction, and particularly discloses an open-cut cast-in-place tunnel main body structure concrete anti-crack construction method. The method comprises a pouring length division step, an anti-crack concrete preparation and mold entering temperature control step and a construction process control step. The method aims at the main contradiction of shrinkage and cracking of open-cut cast-in-place tunnel main body structure concrete, an anti-cracking performance control index and an implementation scheme are provided from two aspects of controlling the temperature (adiabatic temperature rise of the anti-cracking concrete, mold entering temperature, maximum temperature rise, inner-surface temperature difference, center temperature drop rate and temperature difference of mold removal or external thermal insulation measure) of the anti-cracking concrete and shrinkage deformation (7d autogenous volume deformation and 28d deformation of the anti-cracking concrete), a customized complete technical scheme is formed for main structures of different parts, control indexes are clear, universality is high, construction is easy, penetrability shrinkage cracks can be effectively restrained, the leakage problem is solved, and the engineering construction quality is improved.
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Description

technical field

[0001] The invention belongs to the technical field of tunnel construction, and specifically relates to an anti-cracking construction method for concrete of a main structure of an open-cut and cast-in-place tunnel. Background technique

[0002] Although relevant personnel have accumulated a lot of engineering practice in the field of cut-and-cast cast-in-place tunnel structures, the problem of cracking and leakage of concrete is still very prominent, and there is even a saying that "ten tunnels and nine leaks, no tunnels and no cracks". Research and research results show that, except for a small part of the leakage caused by improper joint treatment, most of the leakage is caused by the early shrinkage and cracking of concrete. Therefore, solving the early shrinkage and cracking of concrete is the key to controlling the leakage of cut-and-cast tunnel structures and ensuring the quality of engineering construction.

[0003] Compared with prefabricated immerse...

Examples

preparation example Construction

[0038] This step includes the limitation of the preparation material and performance of the anti-cracking concrete, and the control of its mold temperature.

[0039] The first is the performance requirements of crack-resistant concrete.

[0040] Specifically, considering that the performance requirements of the above-mentioned floor area, side wall area and roof area are not the same for crack-resistant concrete, the preparation of crack-resistant concrete involved in the present invention is divided into three types: floor concrete, side wall concrete and roof concrete. Refer to Table 1 below for the composition ratio design of the three types of crack-resistant concrete.

[0041] Table 1 Composition ratio of three types of crack-resistant concrete

[0042] Unit: kg / m 3

[0043]

[0044] As a choice of raw materials, the performance of cement should meet the requirements of "General Portland Cement" GB 175 and the requirements of CCES01 in "Guidelines for Durability Des...

Embodiment 1

[0068] The anti-crack construction method described in the present invention is applied to the main structure of a certain expressway lake bottom tunnel, which has the following features: figure 2 The two-hole-one-pipe gallery structure shown is constructed using the cofferdam open-cut method. The thickness of the main structure of the buried section in the lake is 1.3m to 1.5m. The design grade of the crack-resistant concrete is C40P8. Very demanding.

[0069] First, divide the pour length.

[0070] Specific reference figure 2 , it can be seen from the schematic diagram of the main structure of the cut-and-cast-in-place tunnel perpendicular to the tunnel length direction that the main structure of the tunnel is divided into successively connected floor areas, side wall areas, roof areas and side wall areas; The bottom plate area is used for subsequent pouring of crack-resistant concrete to form the tunnel floor 11, the side wall area is used for subsequent pouring of crac...

Embodiment 2

[0096] The anti-cracking construction method described in the present invention is applied to the side wall structure of a section of municipal engineering lake bottom tunnel, the concrete design grade is C35P8, and the thickness of the side wall concrete structure is 1.8m.

[0097] First, divide the pour length. In this embodiment, only the pouring project of the tunnel side wall is involved, and the single pouring length is divided into 20 m until the estimated construction length of the entire tunnel side wall is completed.

[0098] Next, prepare the side wall concrete.

[0099] This step includes the limitation of the preparation material and performance of the side wall concrete, as well as the control of its mold temperature.

[0100]Specifically, one is the performance requirements of the side wall concrete.

[0101] Concrete raw materials that meet the quality requirements include cement, fly ash, fine aggregate, coarse aggregate, water reducing agent, Concrete (te...