Waterproof device for underwater cast-in-place pile head in sandy geology

The utility model discloses a sandy geology underwater cast-in-place pile head waterproof device which comprises a pile body, a pile foundation and reinforcing steel bars, the bottom of the surface of the pile body is embedded in the pile foundation, the reinforcing steel bars are embedded in the pile body, and the top of the outer side of the surface of the pile body is sleeved with a sealing sleeve. The sealing sleeve is arranged, a gap between the pile head of the pile body and the pile foundation is sealed through the sealing sleeve, then the movable space of the sealing sleeve is blocked through the fixing steel plate, the sealing sleeve is fixed, meanwhile, the movable space, blocked by the fixing steel plate, of the sealing sleeve is enlarged through the protruding blocks, and therefore the fixing strength is improved; the problem that due to the fact that many gaps exist between slurry and pile foundation concrete after the slurry is poured, water on the top of the pile foundation concrete can flow in