Stability analyses of steel pipe in pipe-jacking and the optimization of wall thickness

Pipe jacking is widely used in the underground construction, but few studies are focused on the pipe wall stability and no specify rule is presented in the codes. According to this situation, theoretical and numerical analysis is applied in research. Through numerical simulation, the inner force and deformation of steel pipe can be obtained, but the control criterion of wall thickness is still in lack. Based on the result of numerical analysis, the deformation of steel pipe is characteristic of arch, so the stability theory of arch in the material mechanics is lead to compute the critical pressure. Comparing the critical pressure with the actual force of steel pipe, the stability of pipe wall can be determined. The steel pipe of intake pipe design of a heat-engine plant is studied as project case, and the stability of pipe wall under different wall thickness is studied using the methods presented. The analysis and optimum design shows that the 22 mm can be determined as the proper wall thickness instead of the original design thickness-34 mm, and the project cost will be decreased significantly.