Analysis of buried oil and gas pipelines crossing active faults: Revisiting pipe-ground interaction

Despite recent developments in computer modelling, the analysis in practice of buried oil and gas steel pipelines crossing active faults usually relies on simplified numerical and analytical beam-on-nonlinear Winkler foundation models. This paper presents recent experimental measurements and numerical estimates of the developing soil reaction, as function of relative soil-pipe movement, used as input in Winkler analysis models. First, we discuss techniques developed to physically model relative soil-pipe movements, as well as imaging-based methods used to document mechanisms of pipe-backfill interaction. Next, we present advanced numerical methods for the analysis of complex pipe-backfill-trench geometries, used to quantify the resistance provided by native stiff soil/rock on pipes backfilled with sand. The presentation concludes with new insights on the mechanics of soil-pipe interaction and recommendations for its modelling in practice, focusing on scenarios not covered by existing guidelines, such as deeply buried pipes and pipes laid in trenches excavated in stiff soil/rock.