Cofferdam construction method

The invention discloses a cofferdam construction method, and relates to the technical field of water conservancy construction. The method comprises the following steps: determining an overwater cofferdam lake filling area, carrying out overwater temporary enclosure on the cofferdam lake filling area, installing a dense-mesh net in the area above the water surface, and installing a geomembrane net in the area below the water surface; steel sheet pile driving is started, meanwhile, rock cofferdam filling operation is conducted till the steel sheet piles are in bridge joint with the two banks of the overwater cofferdam lake filling area, and meanwhile rock cofferdam filling operation on the first side face is completed; earthwork backfilling is conducted, and the whole stone cofferdam is completed; the stone cofferdam above the lake bottom is grouted and filled with cement paste; and a traffic relief road and a construction road are laid on the top of the stone cofferdam. According to the cofferdam construction