Method for reducing longitudinal shrinkage joints of underground comprehensive pipe gallery

Abstract

The invention relates to a method for reducing longitudinal shrinkage joints of an underground comprehensive pipe gallery. The method is characterized in that the stress change of the pipe gallery section is controlled, specifically, the stress making the underground comprehensive pipe gallery generate cracks is reduced through control over shrinkage stress, temperature stress and creep stress, and therefore, occurrence of the shrinkage joints is reduced; when sigma <ck>- sigma <pc> is smaller than or equal to f<tk>, the longitudinal shrinkage joints can be reduced, the sigma <ck> represents anti-crack edge concrete normal stress, and the sigma <pc> represents anti-crack edge concrete pre-pressure stress; through control over the shrinkage stress and the temperature stress in the construction stage, the purpose of reducing stress is achieved, and therefore, occurrence of the cracks is reduced; and through control over intelligent tensioning and by the adoption of cohesive pre-stressed concrete plates in the long-term maintenance stage, occurrence of the creep stress is reduced, and therefore, occurrence of the cracks is reduced.

Description

technical field [0001] The invention relates to the field of building construction, in particular to a method for reducing longitudinal shrinkage joints of an underground comprehensive utility gallery. Background technique [0002] Concrete is a multi-phase composite material, which contains cement mortar as a parent material and coarse aggregate contained therein, and most aggregates themselves are also multi-phase composite materials, including various crystalline or non-crystalline components, and contain different degree of porosity. The hydration reaction of cement turns fresh plastic cement slurry into solidified cement slurry or cement stone, and at the same time converts fresh concrete into solidified concrete, which is a complex chemical and physical process. Creep is closely related to stress, and concrete will still shrink and produce cracks when there is no stress. Concrete shrinkage is a deformation that is related to time and not dependent on load. It is cause...

AI Technical Summary

Problems solved by technology

The normal work of unbonded prestressed steel bars in the structure mainly depends on the anchorage at both ends. Once the anchorage fails for some reason, a large number of cracks are likely to occur, which will pose a hidden danger to the safety of the entire structure, and even lead to continuous collapse.