Random field CEL analysis of pipeline response to spudcan penetration: effects of offset distance and soil strength profiles

To investigate the effects of spudcan penetration on adjacent buried pipelines, a three-dimensional spudcan-seabed-pipeline interaction model was established using the Coupled Eulerian-Lagrangian (CEL) method. Spatial variability of clay undrained shear strength was represented by random fields generated through random finite element method (RFEM) analyses. Pipeline responses, including lateral and vertical deflections and bending moments, were evaluated under offsets d = 4 and 8 m and undrained shear strength profiles su = 10 + 2z and su = 20 + 2z. Results show that increasing the spudcan-pipeline distance attenuates penetration-induced disturbance, leading to smaller deflections, shorter affected lengths and lower peak bending moments. The higher-strength profile generally produces larger bending moments but smaller deflections. At d = 4 m, incorporating random fields amplify both deflection and bending moment, while this influence becomes weak at d = 8 m. These findings support risk assessment and safe offset design for pipelines near spudcan installations.