Prefabricated composite pile with variable-diameter structure

The utility model relates to the technical field of precast piles, and discloses a precast combined pile with a reducing structure, which comprises a pile body, the upper end of the pile body is fixedly connected with a fixed shell, the upper end of the pile body is movably provided with a reducing section, the reducing section is semicircular, the upper end of the pile body is provided with a strip-shaped groove, and the upper end of the pile body is rotatably provided with a screw rod through a bearing. And a first wedge block is arranged on the inner side of the reducing section. According to the technical scheme, through the arrangement of the pile body, the second wedge-shaped block and the fixing rod, in the using process, the first wedge-shaped block can push the second wedge-shaped block, the variable-diameter section is conveniently driven to move towards the two sides, and therefore the upper end of the pile body is adjusted, and the requirement for correspondingly adjusting and changing the outer d