Anti-crack freezing well wall concrete and preparation method thereof

Abstract

The invention discloses anti-crack type freezing well wall concrete and a preparation method thereof. The concrete is C70 anti-crack type concrete, and comprises cement, fine aggregate, coarse aggregate, fly ash, an additive, an expanding agent, fibers and water. On the basis of the mix proportion of the inner wall of an existing freezing shaft, the expanding agent, the fibers and the like are added, and the quantity of the expanding agent and the fibers and a specific preparation method are determined through a mix proportion experiment. Compared with a reference group, the crack-resistant frozen well wall concrete has the advantages that: the early-stage compressive pre-stress is 36.6% higher, the second zero stress time is prolonged by 15%, the cracking temperature drop is increased by 20.7%, the tensile stress increase rate is reduced by 90%, and the cracking stress is increased by 10%. The concrete has high shrinkage compensation and early-stage temperature crack resisting effects.

Description

technical field [0001] The invention relates to the technical field of freezing shaft wall concrete. Specifically, it is a crack-resistant frozen well wall concrete and a preparation method thereof. Background technique [0002] The artificial freezing method is one of the main construction methods for the wellbore to pass through deep alluvium, topsoil, and water-rich sand layers, and has been widely used in deep wellbore construction. At present, the well wall structure widely used in frozen well shafts is double-layer reinforced concrete and plastic interlayer composite well walls. Among them, the inner well wall poured continuously from bottom to top is the main structure for resisting hydrostatic pressure and seepage prevention after the frozen wall is thawed. However, as the depth of the wellbore increases up to one kilometer, the thickness of the inner wall of the frozen wellbore increases accordingly. According to the current code, the wall thickness of the inner l...

AI Technical Summary

Problems solved by technology

It is proposed that the main reason is that the hydration and heat release of the inner wall under the condition of continuous cooling of the outer frozen wall leads to a large temperature difference between the inner and outer walls, resulting in a large early temperature stress. When the temperature stress is greater than the concrete tensile strength, early temperature cracks will occur.

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