Probabilistic investigations on the elastic stiffness coefficients for suction caisson considering spatially varying soils

Abstract

The importance of accurate estimation of elastic stiffness coefficients of suction caisson has been already highlighted in previous works. Nonetheless, studies related to the spatial non-uniformity of the clayey seabed are somewhat limited, and current theoretical solutions are usually established using deterministic soil properties, overlooking the inherent uncertainty of the soil. This study focuses on the elastic performance of suction caisson in spatially random soils using three-dimensional (3D) small strain random finite element analyses within a Monte-Carlo framework. The non-uniformity of soil is mapped by modeling the shear modulus as a random field. The influences of soil profiles, embedment ratios and random field parameters on the elastic stiffness coefficients are comprehensively quantified. Results demonstrate that the spatially varying shear modulus notably alters the failure mechanism, which in turn significantly affects the elastic stiffness coefficients, ignoring soil variation will provide non-conservative predictions. To deal with the uncertainty of soil shear modulus, a series of expressions are developed by adding reliability-related parameters to the existing theoretical solutions, which can be adopted to calculate quantiles of stiffness coefficients corresponding to several given probabilities. The findings of this research may potentially facilitate the elastic performance assessment of suction caisson.