Study On The Critical Geotechnical Parameters And The Thickness Of Large-diameter Steel Jacking Pipe

The jacking pipe, shield and directional drilling are the most widely used trenchlesstechnology. Because of the advantages of the short construction period, the low cost and slightenvironmental damage, the pipe jacking engineering is widely used in drains, oil and gas pipelinecrossing engineering. At present, for the most critical parameters in the design of the pipe jacking-the pipe thickness is more dependent on the designer's experience, mainly due to highspecification design values make significant increase in the cost of the project.In this paper, the key of jacking pipe thickness design-composite deformation modulus'calculation has been meticulously analysed in theory. The paper has proposed the integralcalculation method and steps of jacking pipes thickness and established the relationship amongthe composite deformation modulus, compression and rebound modulus. Finally, the papermodifies the modulus of the standard and employs the finite element software ABAQUS toresearch the rebound and compression mechanical properties of jacking pipe under the soil load.The main contents and the research results of this paper are as follows:(1) Simulating the engineering conditions through the variable parameters, the pipesurrounding soil pressure characteristics and the lumen deformation law depend on the use offinite element analysis software, combined with theoretical analysis proposed pipe design toobtain the optimization theory of critical design problems;(2) On the basis of flexible steel pipe jacking structure and soil deformation coordination,the paper consider the anisotropy of the elastic parameters of natural sedimentary soil, separatelydealing with large-diameter steel jacking pipe top soil resilience and the soil compression of theboth sides;(3) The studies have shown that the existing specification design method is applicable toburied pipe design, but the design that is using for buried large-diameter steel pipe jacking isconservative;(4) The buried large diameter steel jacking pipe display the vertical compression and thetransverse tensile deformation law. To employ the stress path analysis method to verify the lawof soil lateral compression and the vertical unloading rebound;(5) The pipe thickness and compressive modulus coefficient significantly impact themaximum stress of the pipe but the maximum strain. The study propose replacing the soildeformation modulus of existing norms by the soil composite deformation modulus in thejacking pipe design of homogeneous soil buried steel pipe jacking engineering.