One-time pouring and molding construction technology of fully enclosed columns in subway stations with cover-excavation

Abstract

The invention discloses a one-time pouring and forming construction technology for totally enclosed columns of a cover and excavation top-down subway station. The one-time pouring and forming construction technology comprises the following steps that firstly, excavation is performed sequentially from top to bottom, and each layer of upper plates and each layer of lower plates are poured; during pouring, a plurality of rebar casing pipes are pre-buried inside the upper plates and the lower plates; exhaust iron pipes are pre-buried in the lower portions of the interiors of the upper plates; secondly, survey setting out is performed on the closed columns; thirdly, whether the positions of the rebar casing pipes exceed the dimension range of the closed columns or not is inspected; fourthly, rebars are bound on the closed columns; fifthly, closed column formworks are manufactured and erected; sixthly, pouring is performed through all pouring mouths sequentially from bottom to top, vibration is performed during pouring through vibration mouths in the pouring process; seventhly, after concrete reaches the requested strength, the formworks can just be dismantled. The one-time pouring and forming construction technology has the advantages that tight combination between the tops of the closed columns and the upper plates can be guaranteed, and therefore the supporting strength of connection between the closed columns and the upper plate is ensured. Moreover, the construction cycle is short, the closed columns can be poured and formed at a time, it can be guaranteed that the centers and the surfaces of the closed columns are vibrated to be compacted, and no concrete defects are produced.

Description

technical field [0001] The invention relates to a construction technology, in particular to a construction technology of one-time pouring and forming of a fully enclosed column of a subway station by cover-excavation. Background technique [0002] Cover-excavation is a new type of engineering construction method that needs to cross roads, buildings and other obstacles when the underground engineering is done openly. After the ground is excavated to a certain depth, the top is closed, and the rest of the substructure is in the closed area. Construction under the roof. When subway stations are built in busy urban areas, roads are often occupied and traffic is affected. This method can be used when subway stations are located on main roads and traffic cannot be interrupted, and certain traffic flow requirements must be ensured. There are certain defects in the existing cover-excavation construction: 1. The uneven settlement of the closed column during the construction process ...

AI Technical Summary

Problems solved by technology

There are certain defects in the existing cover-excavation construction: 1. The uneven settlement of the closed column during the construction process has a serious adverse effect on the closed column structure system, especially the air hole gap between the top of the closed column and the upper plate is easy to occur, thereby reducing the sealing effect. The support strength of the column to the upper plate; 2. Due to the impact of shrinkage and sinking of the concrete structure of the closed column during the hardening process, cracks inevitably appear, which have an adverse effect on the rigidity, durability, and water resistance of the structure

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