The axial resistance of pipelines is an important input for various pipeline design scenarios including end expansion forces and buckle formation. Although the axial resistance of pipelines on very soft clay soils has been the focus of considerable research, the case of pipelines laid on sand has not received as much attention. Some recent testing at the University of Bristol sought to address this by investigating the interface friction obtained with smooth polymer coatings sheared against a variety of sands at low stress levels and results showed significant divergence from limited industry guidance that exists. The present paper seeks to build on this research by assimilating the results of further experimental work using roughened polymer surfaces. Sands with a wide range in grain size were tested at different densities in the submerged condition and at low stress levels using a shearbox that offers improvements over the conventional apparatus. The results are compared with a variety of previously published research and general trendlines are given.
Henry Milewski, Andrea Diambra, Lawrence W. de Leeuw and Matthew S. Dietz
Keywords: Interface friction, low stress, polymer coating, pipelines, sand, axial resistance, average roughness, coefficient of friction, shear box
Publisher: DFI