During its working life, a pipeline may be subjected to a range of ground loading conditions that were not anticipated within the design. Any threat to pipeline integrity must then be assessed using suitable methods and acceptance criteria. One aspect to consider in this situation is the determination of representative soil loading and restraint values for stress analysis. This aspect is often poorly defined despite the fact that the soil loading and restraint assumptions may be found to exert a significant influence on predicted pipeline performance and integrity. A clearer requirement for the treatment of soil loading and restraint will assist in achieving code compliant pipelines. This will avoid the inadvertent use of the code safety margin to accommodate geotechnical uncertainty and in extreme cases, pipeline failure. The paper presents the methods of soil loading and restraint estimation in common use and identifies the soil parameters required. These parameters are then examined in terms of their range of values. The sensitivity of pipeline performance to loading and restraint bounds is illustrated through examples of uprating(increased pressure and temperature), overburden loading, and ground movement.
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