Ultra-deep water steel cofferdam structure

The utility model belongs to the technical field of ultra-deep water cofferdams, and particularly relates to an ultra-deep water steel cofferdam structure. The steel cofferdam comprises a plurality of steel box units and a plurality of steel cofferdam units, the plurality of steel box units and the plurality of steel cofferdam units enclose a rectangular double-wall steel jacket box structure; a steel box unit is arranged at each of four corners of the rectangle, at least two steel box units are arranged on each side of the rectangle, and the adjacent steel box units are connected through a steel cofferdam unit. According to the rectangular double-wall steel boxed cofferdam, the number of the steel box units is increased on the rectangular double-wall steel boxed cofferdam, and radial axial force is converted into annular axial force by adopting the annularly wrapped steel plate lappets in the steel box units, so that the stress of the rectangular double-wall steel boxed cofferdam is optimized, the stress con