Splayed inner diagonal bracing large-space light single-wall pouring jacket steel cofferdam and construction method

The lower end of a single-wall pouring jacket is arranged on a bearing platform bracket on the outer side of a pier column bearing platform, a sandbag is arranged for sealing the bottom, vertical stiffening ribs are arranged along the four walls of the single-wall pouring jacket at equal intervals, horizontal annular stiffening ribs are arranged on the inner sides of the vertical stiffening ribs, and the horizontal annular stiffening ribs are arranged on the outer side of the single-wall pouring jacket. The two ends of the L-shaped corner section and the two ends of the horizontal connecting section located on the lowermost layer are each provided with a fixing bracket, and the fixing brackets are installed on the top face of the pier column bearing platform. Splayed supports and inner diagonal supports are arranged on the inner sides of the horizontal annular stiffening ribs, one end of each inner diagonal support is fixed to the middle of the horizontal connecting section, and the other end of each inner di