Self-elevating platform, and hydraulic bolt lifting device and method thereof

The invention provides a self-elevating platform, and a hydraulic bolt lifting device and method thereof, and belongs to the field of ocean platforms. The hydraulic bolt lifting device comprises a fixed ring beam, lifting oil cylinders, a movable ring beam, bolt assemblies and a lifting mechanism, wherein the fixed ring beam and the movable ring beam are arranged on a pile leg in a sleeving manner, the lifting oil cylinders are connected between the fixed ring beam and the movable ring beam, and each bolt assembly comprises a first bolt, a second bolt, a first bolt oil cylinder and a second bolt oil cylinder; the first bolt oil cylinder is arranged on the fixed ring beam, the second bolt oil cylinder is arranged on the movable ring beam, the first bolt is fixed to a piston rod of the firstbolt oil cylinder, the second bolt is fixed to a piston rod of the second bolt oil cylinder, and the first bolt and the second bolt are used for cooperating with bolt holes formed in the pile leg respectively; and the liftin