Method for reducing thickness of subsealing concrete of steel cofferdam and preventing seepage

Abstract

The invention discloses a method for reducing the thickness of subsealing concrete of a steel cofferdam and preventing seepage, comprising the following steps of: a. assembling the steel cofferdam and welding an upper circle of shearing resistant structure and a lower circle of shearing resistant structure along the inner wall of the steel cofferdam; b. feeding the steel cofferdam in water; c. welding an upper circle of shearing resistant structure and a lower circle of shearing resistant structure on the outer wall of each steel protecting tube and sequentially punching the steel protecting tubes into a foundation in the steel cofferdam; d. constructing all drilling piles; e. cleaning the foundation in the steel cofferdam and flushing the steel cofferdam and the shearing resistant structures underwater on the steel protecting tubes; f. pouring the subsealing concrete to be combined with the steel protecting tubes, the steel cofferdam and the shearing resistant structure into a whole; and g. pumping water from the steel cofferdam and constructing a bearing platform. According to the method, by arranging the shearing resistant structures, after water in the steel cofferdam is pumped, the force transfer mode of the subsealing concrete and the inner wall of the steel cofferdam and the outer walls of the steel protecting tubes is converted into a bonding force and a shearing force from the mutual bonding force, so that the dereference of the concrete bearing capacity accords with the reliable basis and the thickness of the subsealing concrete can be reduced; and the water seepagae in the steel cofferdam can be prevented.

Description

technical field [0001] The invention relates to the field of cofferdam construction, in particular to a method for reducing the thickness of the bottom-sealing concrete of a steel cofferdam and preventing leakage. Background technique [0002] At present, there are two working conditions for the force calculation of the steel cofferdam back-sealing concrete for bridge foundation construction: one is the calculation of the shear capacity between the back-sealing concrete, the steel cofferdam and the steel casing; the other is the calculation of the bending resistance of the back-sealing concrete; The thickness of the back cover is determined by controlling the above two working conditions. When calculating the shear capacity, the force transmission mode between the back cover concrete and the inner wall of the steel cofferdam and the outer wall of the steel casing is the bonding force between them. The value of the joint force is usually 50-60% of the allowable value in the ...

AI Technical Summary

Problems solved by technology

When calculating the shear capacity, the force transmission mode between the back cover concrete and the inner wall of the steel cofferdam and the outer wall of the steel casing is the bonding force between them. The value of the joint force is usually 50-60% of the allowable value in the code, and the shear stress of the concrete in the code is about 20% higher than the bond force, which cannot give full play to the effect of the shear force, resulting in a large thickness of the back-sealing concrete; and the back-sealing concrete Due to the silt and rust on the surface of the steel cofferdam wall and the steel casing wall, the steel cofferdam and the steel casing cannot be well combined, and there are water seepage channels, so that the steel cofferdam seeps after pumping water, and drainage treatment is required, and the increase in pumping equipment leads to consumption A large amount of electricity will increase the cost, and in severe cases, it will also affect the construction progress and the construction quality of the cap concrete

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