Research on Assessment of Earthquake Liquefaction in Offshore Wind Turbine Based on Dynamic Triaxial Test

Considering the obviously distinctive methods for liquefaction assessment of cohesiveless soils both at home and abroad, this paper compares and summarizes the available methods for assessing the earthquake liquefaction in offshore wind power applications in current stage. Taking an offshore wind power farm project in eastern Guangdong as an example, the simplified SEED method is adopted to assess the liquefaction of soil masses with the laboratory triaxial test based on the survey and drilling data at typical wind turbine positions on the site. Different soil layers, buried depths, relative densities, and confining pressures are considered in the test. This paper plots the relation curve between the dynamic shear stress ratio and the failure vibration frequency of soil samples under the action of cyclic stresses with a constant amplitude, defines the liquefaction resistance index CRR15, and obtains the liquefaction assessment results by comparing the CRR15 with the calculated CSR according to the seismic design requirements. Besides, the paper also compares the dynamic triaxial test results with the liquefaction assessment results upon the specification approach at the field survey site, showing that both results are substantially identical. These findings may be used for guiding the seismic analysis and foundation structure design on the site of the wind power farm project.