Elastic Buckling Analysis of Steel Pipe-Jacking Embedded in the Winkler Foundation

Steel pipe-jacking is widely used in water supply and other pipeline projects because of its low environmental impact and high construction efficiency. The tradeoff between economic benefits and engineering safety renders the wall thickness of such pipes becoming increasingly thinner. Meanwhile, the stratum and surrounding environment become more complex. The buckling of steel jacking pipes is considerably different from the conventional buckling problems due to the pipe-soil interactive behavior. For instance, the stratum provides constraining effect on the outward deflection; whereas, the non-uniform stratum may lead to the reduction in the critical elastic buckling load. Steel jacking pipes are subjected to these complicated loads so that the buckling phenomenon sometime occurs on the pipes. In this paper, the elastic buckling behavior of steel jacking pipes is analyzed by introducing the Winkler Foundation Model. The steel jacking pipes are modeled as cylindrical shells with two simply supported ends. Buckling eigen value analysis is conducted for such a model subjected to the axial force. The friction resistance is neglected due to the application of grouting. The surrounding soil is modeled as a series of closely spaced, mutually independent, and linear elastic spring elements. The influences of various parameters are discussed using the numerical analysis. Results obtained will inform the design of an economic and efficient steel jacking pipe.