Abstract: The ground movement caused by tunneling will induce extra deformation on adjacent buried pipelines, even damage. Research on soil-pipeline interaction indicates that higher soil stiffness will lead to a conservative bending moment. An equivalent linear method based on Winkler subgrade model is proposed for modifying soil modulus and evaluating the maximum bending moment for continuous pipelines affected by excavation. The method takes account of tunneling-induced soil nonlinearity by a stiffness degradation model, in which soil average deviatoric strains caused by green field displacement are calculated together with a multi-layer-disc elastic model in order to consider soil nonlinearity induced by soil-pipeline interaction. The validity and rationality of the approach is proved by comparing with elastic theoretical solution and centrifuge model test.

Key words: tunneling, soil nonlinearity, continuous pipelines, Winkler subgrade model, layer-disc elastic model