Influence of ground-surface deformation in pipe jacking construction with parallel differential section

The development of urban underground space and traffic promotes the wide application of large section pipe jacking technology in urban tunnel construction.The functional requirements of parallel pipe jacking tunnel are different, so shapes and sizes of the section are also different.Based on the double-line parallel pipejacking tunnel with difference large section under through the main road in the city, a three-dimensional finite element calculation model is established for systematic analysis.At the same time, combined with the measured results of the field pipe jacking project, the characteristics and influencing factors of ground-surface deformation under different sections and different construction sequence of parallel pipe jacking are studied.The results show that the surface deformation curve caused by parallel differential section pipe jacking construction is Ⅴ-curve, and the peak point of the surface deformation curve gradually shifts from the large section rectangular pipe jacking axis to the two pipe centers.The surface settlement on the left side of the axis of the small section rectangular pipe jacking is larger than that on the right side of the axis.Construction of large section rectangular pipe jacking on the left line is more beneficial to control surface deformation.The influence of section size change on surface deformation is 30%, and the influence of process on surface deformation is 8%.The influence of section size difference on surface deformation is greater than that of process difference.The study on the influence of parallel differential section pipe jacking construction on surface deformation can provide theoretical basis and experience for future related parallel large section pipe jacking projects.