The interaction between the seabed and unburied pipelines is one of the key uncertainties associated with deepwater and/or high pressure, high temperature (HPHT) pipeline design. Emerging research is shedding light on this important topic that is not currently well understood. BP has amassed a considerable quantity of data from different basins ranging from conventional in situ measurements of soil properties (supplemented by two campaigns using Fugro’s SMARTPIPE®) to model testing at the Norwegian Geotechnical Institute (NGI) and the University of Western Australia (UWA). Added to this, standard and advanced low stress inter-face shear testing has been carried out in laboratories at the University of Texas, Austin, UWA and Fugro.
These tests were designed to address the key mechanisms governing axial pipe-soil interaction behaviour, spanned a large range of pipe properties and sliding velocities, and included episodes of post-sliding reconso-lidation. New data from all of these sources are given in this paper, along with a theoretical framework devel-oped to synthesise these results and contribute to improved practice for the design of pipelines that are suscep-tible to walking, buckling and other forms of movement.