Leakage of underground water pipes: repair welding treatment. Water leakage in pipeline welds should be stopped for repair welding, and cast iron electrodes should be used for cast iron pipes. Before repair welding, in addition to cleaning the surface, a small hole should be drilled at each end of the crack, and the crack should be beveled before welding. Finally, the small hole should be repaired, and the welding joint should be treated with anti-corrosion. Underwater pipe leakage: the flange is leaking, replace the rubber gasket, arrange the bolts according to the number of flange holes, pay attention to the symmetrical tightening of the bolts. If it is caused by the subsidence of the foundation, a buttress shall be added to the pipeline. Underwater pipe leakage: Socket leakage. If the socket of cement pipe or cast iron pipe leaks, the sealing packing at the leaking place should be removed (be careful not to shake too much), rinse it clean and pound it with oil hemp, then seal it with blue lead or asbestos cement, or add a steel sleeve to deal with it. If there is water leakage at the plastic pipe joint, the joint can be cut off and reconnected with an expansion joint, or a steel sleeve and a rubber ring can be used to fasten it. Water leakage in underground water pipes: large areas of water leakage, cutting off the leaking section of the steel pipe and re-welding a section of the steel pipe or repair welding a steel plate with the same curvature and similar thickness at the crack. The cast iron pipe is a circumferential crack, and a steel casing can be added, and then green lead or linoleum or asbestos cement is injected between the steel casing and the iron pipe. If it is a longitudinal crack, small holes should be drilled at both ends of the crack to prevent the crack from extending, and casing treatment should be added. A steel bar is welded at the inner wall of both ends of the casing at 15-20mm, and the diameter is determined by the gap, which can prevent the filling material from falling into the tube and make the filling gap uniform.
