Effects of tunnelling on existing pipelines in layered soils

Soil movements caused by tunnel excavation can adversely affect and even damage underground pipelines in the vicinity. This paper provides a continuous elastic analysis in finite difference form aimed at simulating the responses of both continuous and jointed pipelines subjected to tunnel-induced soil movement in multi-layered soils. The effects of soil stratification on pipeline behaviour are analysed using the mathematical Hankel transform and transfer matrix technique, and the behaviour of the joints of a hinged pipeline is modelled as a plastic hinge. The accuracy of the proposed method is verified by comparison with a published study of elastic solutions used in homogeneous soil and centrifuge model tests. Finally, two case studies and a parametric analysis of the effects of different soil profiles in a sandwich soil model are presented to demonstrate the performance of the proposed method.