Pipe-soil interaction mechanism during pipeline upheaval buckling in loose saturated sand

This paper presents the observed deformation and strain fields around model pipeline based upon results obtained from eight full-scale vertical pull-out tests on pipes immersed in saturated loose sand in the laboratory. It is found that the pipe-soil interaction mechanism during the uplift event can be divided into four stages: Pre-peak, near-peak, post-peak transition, and post-peak steady-state. In addition, the evolutions of the “uplift zone” and “infilling zone” above the pipelines during these four stages are discussed, with considerations for a range of embedment ratios and pipe diameters