Longitudinal cofferdam structure

The invention belongs to the technical field of water conservancy and hydropower engineering, and particularly relates to a longitudinal cofferdam structure. The longitudinal cofferdam structure comprises a longitudinal cofferdam body of a concrete structure, a U-shaped groove is formed in the middle of the longitudinal cofferdam body in the length direction of the longitudinal cofferdam body, and a rock ballast backfilling structure is arranged in the U-shaped groove. The U-shaped groove is formed in the center of the longitudinal cofferdam body in the width direction. The width of the U-shaped groove is not larger than 50% of the width of the longitudinal cofferdam body. The depth of the U-shaped groove is not larger than 60% of the height of the longitudinal cofferdam body. The two side walls of the top of the U-shaped groove are connected through concrete precast beams which are transversely arranged, and the concrete precast beams are arranged at intervals in the length direction of the U-shaped groove.