Calibration of Verley and Sotberg Soil Resistance Model for Pipelines Placed on Calcareous Soils

On-bottom stability of subsea pipelines has been the focus of substantial research in recent years with particular emphasis on the topic of pipe-soil interaction. Numerous models have been developed to predict the pipe-soil interaction behavior under combined vertical and horizontal loading scenarios. The Verley and Sotberg energy based soil resistance model for silica sand is among these models. The model is recommended by Det Norske Veritas (DNV) and widely accepted and used by subsea pipeline design industry to model the pipe-soil interaction on silica sand soils. Calcareous sand soils are found in many of the world's offshore hydrocarbon development regions including offshore of Western Australia. The engineering characteristics of the calcareous sand are different from those of the typical silica sand soils. As such, Verley and Sotberg parameters for silica sand soils are not suitable for calcareous sand soils. This paper presents a calibration of the Verley and Sotberg silica sand soil resistance model for calcareous sand soil conditions using the results of a set of centrifuge tests of a pipe model on calcareous sand soil.