Study on the Lining Design Methods for the Trenchless Rehabilitation of Urban Water Mains

With the frequent occurrence of pipe-failure accidents of urban water mains and the increasing application of trenchless rehabilitation technology in municipal pipeline systems, this paper focuses on a crucial matter of the trenchless rehabilitation of urban water mains: lining design. Rational design of linings plays a significant role in a certain trenchless pipe rehabilitation engineering, which is directly related to the final structural strength of the rehabilitated pipe system, the flowing capacity of the rehabilitated pipe and the final cost of the project. As water mains are pressure pipes and complicated pressure waves may occur in the running period, the lining design of water mains is quite different from the pipes which mainly withstand external pressure. However, the existing lining design theory mainly concerns external pressure, seldom concerning internal pressure. So this paper tries to establish a set of new lining design methods for the rehabilitation of water mains, concerning external pressure as well as internal pressure waves. Based on the summary of the existing lining design theories, the lining design methods in this paper are established through mechanical analysis of the conditions of pipe loads and the strength of the rehabilitated water mains resisting inner and outer loads. Through a series of mechanical analysis and references of existing lining design theories and related mechanical models, this paper finally provides a set of relatively effective lining design methods for different trenchless rehabilitation techniques using in water mains. The study in this paper will offer references for the future trenchless rehabilitation of urban water mains.