Numerical study on lateral buckling of pipelines with imperfection and sleeper

Lateral buckling is an important issue in unburied high-temperature and high-pressure (HT/HP) subsea pipelines systems. The imperfection-sleeper method is one of the most well-known methods used to control lateral buckling of HT/HP pipelines. Pipelines-sleeper-seabed numerical models are established and verified to analyze the buckling behavior of pipelines using the imperfection-sleeper method. The influence of six main factors on lateral buckling behavior is investigated in details based on the numerical results. Equations of buckling displacement (buckling displacement is defined by the final displacement of the middle point of the pipelines), critical buckling force, and buckling stress (Mises stress) are proposed using the gene expression programming technique. These equations show good accuracy and can be used to assist in the design of sleepers and assess the compressive and stress levels of pipelines.