Lateral buckling analysis of subsea pipelines on nonlinear foundation

Lateral soil resistance plays a significant role in lateral buckling, which is a main consideration in the design of subsea pipelines. In this study, a new lateral soil resistance model is proposed to describe the lateral resistance force-displacement relation. It shows a good agreement with existing test results. Based on the new lateral soil resistance model, analytical solution for the lateral buckling of subsea pipelines with initial imperfections is presented. The exact formula to determine the critical half-wavelength is also presented. The effects of initial imperfection parameters, soil properties and parameters, and lateral soil resistance models on critical force of lateral buckling are discussed. Results show that the capacity of subsea pipeline against lateral buckling increases with the increase of the initial half-wavelength, submerged unit weight of soil, and vertical load. It decreases with the increase of the initial imperfection amplitude, soil undrained shear strength, and breakout displacement. The critical forces of lateral buckling in and away from the buckled region both depend on the exact lateral soil resistance model and initial imperfection parameters.