Investigation of impact of submarine landslide on pipelines with large deformation analysis considering spatially varied soil

In-situ soil properties exhibit natural spatial variability. In this study, the Karhunen-Loève (K-L) expansion method and the Coupled Eulerian-Lagrangian (CEL) method are integrated to simulate large deformation behavior of slopes with spatially varied shear strengths. The impact on pipelines induced by spatially varied landslides is investigated. The mean value of the maximum impact force is significantly larger than the deterministic value obtained for a homogeneous slope. The proportion of the maximum impact force from stochastic analysis that exceeds the deterministic value is much greater than 50%. This result shows that the deterministic study can significantly underestimate the damage of pipeline by a landslide if the spatial variability is not considered. The uncertainty of the impact force increases with the coefficient of variation (COV) of the undrained shear strength and decreases with the reduction of horizontal correlation length. By considering buckling failure and plastic yielding failure of pipelines, the failure probabilities are assessed and a pipeline design based on stochastic analysis for spatially varied slope is presented.