ZHAO Liu-yuan, SHAN Zhi-gang, WANG Ming-yuan. Analysis of liquefaction characteristics of horizontal site of offshore wind farm under earthquake in the South Yellow Sea[J]. 2022, 43(1): 169-180.
ZHAO Liu-yuan, SHAN Zhi-gang, WANG Ming-yuan. Analysis of liquefaction characteristics of horizontal site of offshore wind farm under earthquake in the South Yellow Sea[J]. 2022, 43(1): 169-180.DOI: 10.16285/j.rsm.2021.0336.
which is the most concentrated area of offshore wind farms in China. At present
it accounts for about 70%?75% of the total installed capacity of China. The overburden layer thickness in this area is very large
soils along the pile length depth (generally 40?60 m) are mainly silty sand
silt and silty clay
especially the easily liquefied silty sand silt layer at the depth of 20 m below the mud surface. The South Yellow Sea is also an earthquake activity area in China. Therefore
the seismic liquefaction characteristics of the horizontal site of offshore wind farm in this area are studied. Firstly
based on the statistical characteristics of drilling data of 50 sites in an offshore wind farm in the South Yellow Sea
the generalized formation model is established. The soil dynamic parameters are calibrated based on dynamic triaxial test and resonance column test
and three ground motions are inversed (EL-Centro
Northridge and Kobe)
and the peak ground acceleration (PGA) near the surface is adjusted to 0.05g
0.10g
0.20g and 0.40g respectively
and the site liquefaction is researched. The characteristics of excess pore pressure ratio
total settlement and layered settlement under earthquakes are analyzed. It is found that the strata in this area are liquefiable soils
the excess pore pressure ratio of each layer is less than 1.0 when input PGA is 0.05g
and the total settlement is about 1 cm. When input PGA is 0.10g and 0.20g
only the surface layer (within 12 m) is completely liquefied
and the total settlement is 10 and 17 cm respectively. When input PGA is 0.40g
the 20 m strata below the mud surface are completely liquefied
and the total settlement is about 30 cm. Under different earthquakes
the settlement of surface soil (12 m) accounts for the largest proportion (more than 95% when PGA is 0.10g and 0.20g). Therefore
the liquefaction characteristics of offshore wind farm under earthquakes should be considered for turbine pile foundation.