Method of reducing concrete hydration heat of cast-in-place pile in permafrost region

Abstract

The invention relates to a method of reducing the concrete hydration heat of a cast-in-place pile in a permafrost region. The method comprises the following steps of (1) constructing in the permafrost region, and digging a foundation pit for the cast-in-place pile according to a design requirement; (2) computing the hydration heat release of concrete needed by the cast-in-place pile according to a routine method, and computing the various needed parameters of a hot stick according to the routine method; (3) binding a reinforcement cage according to the design requirement, and fixedly arranging a sleeve at a required design position in the reinforcement cage after the binding is completed; (4) arranging the hot stick in the sleeve, and hoisting the reinforcement cage into the foundation pit for the cast-in-place pile after fixed arranging of the hot stick is completed according to a confirmed hot stick embedding length; (5) preparing and stirring the concrete which is mixed with an anti-freezing agent according to design grade requirements, pouring the concrete in the foundation pit for the cast-in-place pile, immediately covering with a thin film after the pouring is completed, and then covering with a straw curtain or heat preservation materials for heat preservation; (6) pulling out the hot stick and carrying out follow-up construction according to the routine method. According to the method of reducing the concrete hydration heat of the cast-in-place pile in the permafrost region, disclosed by the invention, the refreezing time of frozen soil can be reduced, and the construction is simple and convenient.

Description

technical field [0001] The invention relates to a method for reducing the heat of hydration of concrete, in particular to a method for reducing the heat of hydration of concrete for bored piles in permafrost regions. Background technique [0002] In the permafrost region, the annual average temperature is lower than 0°C, and a layer of permafrost that does not melt for many years is formed at a certain depth underground, which is called permafrost. During the alternation of winter and summer, the permafrost that melts in summer can only reach a certain depth. The distance from the thawed soil layer on the ground to the top of the permafrost is called the upper limit of permafrost. The general depth is about 2m, but it remains basically stable during the interannual change. It is precisely because of the existence of permafrost that the spatial distribution characteristics of groundwater are fundamentally different from those in general areas. The infiltrating water such as p...

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Problems solved by technology

[0006] The above method can solve the engineering problem to a certain extent, but the concrete bored pile goes deep into the underground permafrost, and under low temperature conditions, it needs to increase the strength and reduce the heat of hydration, so the above method does not fundamentally solve the problem of concrete strength and low hydration. Therefore, it is one of the important problems to be solved urgently in engineering construction to ensure the strength of concrete pouring piles and the minimum thermal disturbance of hydration heat to frozen soil.

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