Construction method for tower crane foundation

The invention relates to a construction method for a tower crane foundation, and belongs to the technical field of cranes for walls of buildings or similar structural pieces support. The construction method is used for solving the problems that the construction cost is high and the construction difficulty is large due to that situation that the arrangement of the tower crane foundation occupies a construction transporting channel or needs to construct a plurality of cast-in-place piles. The construction method comprises the steps that 1, two bored cast-in-place piles which can reach the elevation position at the bottom of a tower crane bearing platform are constructed on the outer side of a foundation pit side by side in a spaced mode, and reinforcing steel bars at the upper end of the bored cast-in-place piles extend into the bearing platform; 2, reinforcing steel bars on the top of a underground diaphragm wall are dug out and elongated into the tower crane bearing platform, and the underground diaphragm wall is elongated to the elevation position at the bottom of the tower crane bearing platform by pouring concrete; 3, soil bodies in the range of the bearing platform is excavated, a base layer poured in the elevation position at the bottom of the bearing platform serves as a soffit formwork of follow-up bearing platform construction; 4, the reinforcing steel bars of the bearing platform are bond above the base layer, and the reinforcing steel bars of the bearing platform, and the underground diaphragm wall and the elongated reinforcing steel bars of the bored cast-in-place piles are enabled to be fixedly connected into a whole; and 5, a tower crane anchor foot is placed on the reinforcing steel bars of the bearing platform, and the bearing platform is formed by pouring the concrete.