摘要

An upheaval buckling solution is proposed using a preheating method combined with constraints from two segmented ditching constructions, which are scheduled before and after preheating. In this solution, some selected pipe segments along the route were curve-laid and preserved resting on the seabed in the first ditching construction, while other straight segments were trenched. The subsequent hot water flushing operation induced the curve-laid segments to buckle on the seabed, and then these prebuckles were laterally constrained by the second ditching operation carried out during preheating. After preheating, the cooling rebound of these prebuckles was constrained by the new trenches, and axial pretension was induced in the pipe wall to offset the axial compression in service and upgrade the thermal stability of the entire pipeline. A detailed design approach is provided in this paper, and corresponding Finite Element Model (FEM) verification is given for an example pipeline.