Quick-speed sealing compensating method of submarine pipeline welding line joint and locking type sheath used

The invention provides a submarine pipeline weld joint rapid mending method. A thermal contract tape is twined round or thermal contract tube coating is covered on the weld joint of a steel pipe and the exposed outer surface of the steel pipe near the weld joint. The invention is characterized in that when encapsulating, the inner surfaces and the side surfaces of a half-barrel shaped upper sheathing and a lower sheathing are coated with newly mixed polyurethane and covered on the coating on the steel pipe outer surface immediately. When positioning buckles of the upper and the lower sheathings are buckled with each other, a position fixing stick is inlayed into a groove of the positioning buckle. Then a strapping tape is used for connecting the upper and the lower sheathings with a balance weight layer. The buckling sheathing for the rapid mending way comprises the half-barrel shaped upper and lower sheathings, the positioning buckles buckled with each other and arranged on the butting edges and surfaces of