Seismic responses of suction bucket foundation in liquefiable seabed considering spatial variability

Abstract

The abundant wind energy happens to be distributed along the seismic regions with potential liquefaction. Offshore wind turbines have to be built in these regions for high power generation efficiency. The earthquake-induced liquefaction affected by the natural variability of the seabed makes the safety assessment of suction bucket foundations a challenge. The seismic responses of the laterally-loaded suction bucket foundation in spatially variable soil modeled by an advanced constitutive model were investigated using an FE- FD method. The SPT-(N1)60cs was considered a random variable and the seabed was modeled as a non-Gaussian random field by the Cholesky decomposition technique. The seismic responses were described by the Monte Carlo simulation and the FE-FD method. Statistics of the tilt and the liquefaction potential index influenced by the coefficient of variation and the scale of fluctuation were investigated. The stochastic model was compared with the deterministic model. The liquefaction mechanism and failure mechanism of the suction bucket foundation in random soil were investigated. The tilts and liquefaction may be underestimated without considering the soil spatial variability. Safety factors were introduced into the calculation of the failure probability of the suction bucket foundations. The simulations provide insight into the nonlinear behavior of suction bucket foundations considering the liquefaction of spatially variable soil.