Cofferdam structure and construction method

The invention relates to the technical field of hydraulic engineering and discloses a cofferdam structure and a construction method. The cofferdam structure comprises a bank core and a pressure top arranged above the bank core. The bank core comprises a sand bag filling layer which is arranged on a silt layer. Geotechnical cloth is arranged on the outer side, above and the inner side of the sand bag filling layer. An outer protecting slope is arranged above the geotechnical cloth on the outer side of the bank core. Protecting feet are arranged on the bottom of the outer protecting slope. An inner protecting slope is arranged above the geotechnical cloth on the inner side of the bank core. The inner protecting slope is provided with a first steel plate pile inserted into the silt layer. Thesand bag filling layer is closely attached to the silt layer. The sand bag filling layer has a function of first layer water stopping. The first steel plate pile has a function of second layer waterstopping. The outer protec