Cast-in-situ superposed construction method of heavy concrete roof structure system

The invention discloses a cast-in-situ superposed construction method of a heavy concrete roof structure system. The construction method comprises the following steps that S1, a base plate is poured with concrete; S2, a wall reinforcement cage is installed on the cast-molded base plate, after the wall reinforcement cage is installed, the concrete is poured from the bottom to the required height ofa side wall, pouring is stopped, and pouring of the side wall is completed; S3, a support frame and an arch template are erected between the upper ends of the two cast side walls, arch plate steel bars are installed, the concrete is poured, and the first pouring of a node is completed; S4, the concrete is continuously poured between the wall reinforcement cage and the arch plate steel bars to complete the second pouring of a dark arch layer; and S5, flat top layer steel bars are installed, the concrete is poured, and the third pouring of the flat top layer is completed. According to the cast-in-situ superposed constr