Nonlinear analysis on buried pipelines effected by tunnelling

Abstract

Tunnel excavation may have impact on adjacent pipelines. Ignoring soil nonlinearity, the analysis of responses of pipelines under tunnel excavation will exhibit conservative results. A Winkler subgrade reaction model is developed, in which soil nonlinearity is considered based on the soil stiffness degradation model and the soil shear strain along the pipeline. The soil shear strain for the tunnel-soil-pipeline interaction is evaluated from two aspects. One is the tunnel excavation induced soil strain from the free soil movements. The other is the pipeline-soil interaction induced soil strain, based on a multi-layer-disc elastic model for a laterally loaded pile. The rationality of the Winkler based method in considering soil nonlinearity for the problem of tunnel effects on adjacent pipeline is proved against the published elastic continuum solution.