Boundary element model for analysis of the mechanical behavior of existing pipelines subjected to tunneling-induced deformations

The mechanical behavior prediction for existing pipelines induced by tunneling is usually based on the assumption that the ground is homogeneous. Actually, layered formations with different soil properties are usually encountered in situ and the effects of soil stratification should be taken into account. Based on the boundary element model, a displacement controlled two stage method is presented to predict the deformation behavior of existing pipelines subjected to tunneling-induced deformations in layered soils. The green field displacement profile for layered soils during tunneling is firstly obtained, which is then imposed onto existing pipelines to enable quantifying the interaction effect of tunneling-induced ground movements on pipelines in layered soils. The accuracy of the proposed method is demonstrated with centrifuge model tests, site investigation data, and displacement controlled finite element analyses. The results discussed in this paper indicate that the proposed method can be used to estimate the interaction mechanics for tunnel–soil–pipeline systems in multi-layered soils with higher precision.