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

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.

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...

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Problems solved by technology

In addition, by summarizing the existing literature and engineering practice, it is found that reducing concrete constraints, reducing concrete temperature shrinkage, or simply combining multiple technological measures can effectively reduce the degree of shrinkage cracking of concrete, but the problem of concrete shrinkage cracking has not been completely solved.

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