Anti-seepage cofferdam structure and construction process

The invention relates to anti-seepage cofferdam structure and a construction process. The cofferdam structure comprises a vertical anti-seepage body arranged in the middle of the end face of a cofferdam, wherein the bottom of the anti-seepage body extends to be embedded into a river bed covering layer, a main body of the anti-seepage body is formed by filling a multi-layer gel and sand gravel mixture, a vertical anti-seepage insulating layer is arranged on one side of the anti-seepage body and is a layer of geomembrane clamped between two geotextiles, a trapezoid cofferdam body is arranged on the other side of the anti-seepage insulating layer, and a lead wire gabion is arranged on the other side of the anti-seepage body. The construction process comprises using a backhoe excavator to remove large stones in a basic region after a temporary cofferdam is built; then using the backhoe excavator to dig a groove with 1.2m width and 3m depth along the cofferdam axis, and back filling the multi-layer gel and sand gravel mixture in layers to construct the anti-seepage cofferdam structure. The anti-seepage cofferdam structure is simple in structural style, the construction method is easy, and the anti-seepage effect is good. A construction period is shortened, fund is saved, and a simple and effective method is provided technically.