Reliability-based design for lateral breakout resistance of pipelines under large lateral displacement in spatially random soils

A reliable evaluation of the lateral breakout resistance acting on the pipeline during large lateral displacement is essential for the design of controlled subsea pipeline buckling. However, most previous studies are based on deterministic analysis and are limited to homogeneous soil. Given that marine clay layers demonstrate considerable spatial variability, the appropriate incorporation of such variability into the assessment of pipeline lateral breakout resistance possesses substantial engineering practical significance. To fill this research gap, this study conducted repeated large-deformation finite element calculations combined with three-dimensional random fields within the Monte Carlo framework, systematically simulating the process of pipeline lateral displacement. The findings demonstrate that the spatial variability of soil strength significantly affects the range of mobilized soil and its internal strength characteristics, thereby influencing the pipeline lateral breakout resistance. The random lateral breakout resistance factor exhibits a scattered distribution that can be approximately fitted by a log-normal distribution, and its dispersion is significantly affected by the coefficient of variation of soil strength and the horizontal fluctuation scale. Finally, the proposed framework for deriving safety factors from target failure probabilities offers a new approach for controlled pipeline buckling design in spatially variable soils.