Uplift mobilisation resistance of subsea pipelines in loose sand

Upheaval buckling (UHB) is a well-known phenomenon associated with buried high-pressure high-temperature pipelines. A large number of research studies have been undertaken in the last two decades on developing reliable uplift resistance mobilisation models from which the current standards and recommendations are based. This paper examines Technip's extensive database consisting of experimental and numerical studies concerning sandy backfills only. The peak uplift mobilisation distances obtained are compared with the current DNV recommendations and a recent experimental study undertaken at the University of Cambridge. The trends obtained indicate differences associated specifically with the lower backfill cover depths and suggest that the current recommendations need to be updated. A new improved peak mobilisation distance model, which is able to capture the relevant data with a distinction made between very loose and loose sand backfill, is offered.