Method for lowering large cofferdam

Abstract

The invention discloses a method for lowering a large cofferdam, and relates to the technical field of bridge foundation construction. The method comprises the following steps that a transverse bottom bay and a longitudinal bottom bay in the cofferdam are communicated through an inner communication pipe, bottom bay covers are arranged at the tops of the bottom bays, and a communicated sealed bottom bay system is formed; guide pipe systems with water drawing devices are welded to the top of the sealed bottom bay system, and each guide pipe system comprises one end communicated with the sealed bottom bay system and the other end stretching into water in the lowering process; the cofferdam is transported in a floating mode and fixed, water in the sealed bottom bay system is drawn out, and when the cofferdam floats upwards to be separated from a hanging pile telescopic beam, the hanging pile telescopic beam is dismounted; water is poured into the sealed bottom bay system, the cofferdam is lowered in place, the hanging pile telescopic beam is fixed, and the water drawing device is dismounted; concrete is poured into the sealed bottom bay system through the guide pipe systems; bottom sealing construction is carried out; the guide pipe systems are dismounted. According to the method, the cofferdam can rise or sink freely at different water levels fast and stably, construction is safe, the construction period is shortened, and materials are saved.

Description

technical field [0001] The invention relates to the technical field of bridge foundation construction, in particular to a large-scale cofferdam construction method. Background technique [0002] see figure 1 and figure 2 As shown, the traditional cofferdam lowering system includes double walls of the cofferdam, a steel casing 3, an open bottom compartment 4, a telescopic beam for hanging piles 7, and a heavy-duty lifting and lowering device 1. The traditional cofferdam lowering construction method is as follows: After the cofferdam is floated in place, the elevation of the cofferdam is adjusted by adding water or pumping water into the double walls of the cofferdam, and the telescopic beam 7 for hanging piles is welded to the steel casing 3 to complete the steel casing 3 pile foundation construction. Then adopt the heavy-duty lifting and lowering device 1 to lift the cofferdam 2, remove the hanging pile telescopic beam 7 from the steel casing 3, and then use the heavy-du...

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