Underwater quick connection structure for jacket expansion and use method thereof

The invention relates to an underwater quick connection structure for jacket expansion and a use method thereof, the underwater quick connection structure comprises a guide device, the guide device is a hollow cylinder structure with a trumpet-shaped opening at the top end, and the guide device and a jacket to be expanded are integrally designed; the butt joint device and the guide device are designed in a split mode, the butt joint device comprises a fixed stand column, an inverted horn mouth and a connecting plug pin, the upper end of the fixed stand column is fixedly connected with an external expansion leg, the lower end of the fixed stand column is connected with the upper end of the inverted horn mouth, and the lower end of the inverted horn mouth is connected with the connecting plug pin; and the fixing assembly comprises a plurality of wedge-shaped blocks and a packer, the wedge-shaped blocks are evenly distributed in the circumferential direction of the inner wall of the guiding device and arranged a