Impact of Soil Spatial Variability on the Performance of Suction Caissons in Sand

With the advantages of low construction costs and rapid installation, suction caissons are widely used as foundations in offshore engineering. This study investigates the influence of spatial variability in the compression-to-extension strength ratio of soil on the ultimate moment load, ultimate rotation, and failure mechanism of suction caisson foundations in sandy soils under horizontal loading. The upgraded SANISAND-MS model is employed to accurately capture sand behavior. A three-dimensional finite element analysis, combined with random field simulation of soil's spatial variability, simulates the response of laterally loaded suction caissons in spatially varying soils. Results indicate that spatial variability leads to a significant discrepancy between the ultimate load in random and uniform soils. Assuming uniformity in c overestimates the ultimate load and rotation. These findings highlight the importance of incorporating reliability indices in the design process.

Keywords: Offshorefoundation, Suction caisson, Spatial variability, Random field, Monte Carlo simulation.