Study On Large Diameter Steel Pipe Bursting In Changzhou And Preventive Countermeasures

Water distribution system in modern society is ought to be a system that is safe, stable, efficient and low consumption. To enhance the security of water distribution system is fundamental element of sustainable development of our country. Therefore, there are potential menaces, which restrict development of modern water industry. The high frequency of pipe bursting is one of the potential menaces.The pipe bursting phenomenon has been paid more attention by the public. This paper describes an investigation of a large-size steel pipe in Changzhou, which is 1620 mm in diameter and 17.612 kilometers in length. It has burst failures frequently these years. The conclusion is base on analysis on pipe burst information recent years, taking field samples and calculation. Preventive measures are presented according to the conclusion. Also, the causations of pipe bursting of other pipes are briefly presented. This study aims at providing theoretical practical basis for design, construction and operation of distribution piping system and offering reference for actual projects.In order to asress the mechanism of pipe bursting event, theoretical analysis is required firstly. There are many causes as stress, corrosion, material quality, the effect of air pot and water hammer, foundation settlement, savage construction, etc. With respect to this large-size steel pipe, information of pipe bursting event in Changzhou and adjacent cities was collected and the corrosion behavior of soil around pipeline was evaluated. The consideration also consisted of allocation of the pipeline and the setting of air relief valves.The conclusion based on above analysis showed that, it is the axial stress caused by difference in temperature and water hammer induced by air pot that mainly caused the pipe bursting. As the steel pipe was not welded normatively and was corroded by the soil, the weld is weaker than pipe body. Because of scarcity or aging of air relief valves, it is easy for the air to accumulate in the pipe. In winter, thermal stress strengthened the axial stress of the pipe. At the same time, air pot induces water hammer. The two processes strengthen each other and instantaneous high pressure made the weak weld broken.Three countermeasures have been proposed to solve the problem: Install flexible joints, install more air relief valves, and clean out imposed load. According to these suggestions, Changzhou Water Supply Group Co., LTD reconstructs the pipeline.