Special-shaped structure overflowing surface concrete formwork of drainage and water retaining building and construction method of special-shaped structure overflowing surface concrete formwork

The invention relates to the technical field of special-shaped structure overflowing surface concrete construction, in particular to a special-shaped structure overflowing surface concrete formwork of a drainage and water retaining building and a construction method. The arc-shaped template protrudes downwards, the left and right ends are respectively connected to the vertical templates, the front end is connected to the front end of the top template, and the rear end is connected to the lower end of the rear template; the vertical template is connected to the side wall template below; the stair plates comprise a plurality of transverse plates and vertical plates, one ends of the vertical plates are connected to the tail ends of the transverse plates, the other ends of the vertical plates are connected to the front ends of the other transverse plates, and stepped steps are formed; the front ends of the stair plates are connected to the tops of the arc-shaped formworks, and the rear ends of the stair plates ar