The soft clay with low strength is widely distributed in the offshore area of China

the evaluation of its engineering properties will directly affect the design and safe operation of wind turbine foundation. Piezocone penetration test is the most widely used in-situ test method in offshore geotechnical investigation

which has less disturbance on soil. The disadvantage is that soil parameters can only be obtained through interpretation

which are site specific. Based on an offshore wind power project in Jiaxing offshore area of Hangzhou Bay

Zhejiang province

this paper carried out laboratory tests

in-situ piezocone penetration test. The range of calibrated CPTU cone factor Nkt for muddy silty clay in Hangzhou Bay offshore area is from 14.15 to 30.18

with a total average value of 20.25. The calibration results show that the cone factor N is negatively correlated with pore pressure ratio B

but positively correlated with water content w

void ratioe

liquid limit w

plastic limit wp and plasticity indexI. And a multiple regression formula between N and pore pressure ratio Bq

plasticity index I are obtained. By applying the N correlations into the wind farm at Pinghu offshore area near this project

the results show that the correlations between water content w

void ratio e and cone factor N and multiple regression formula between N and pore pressure ratio B

plasticity index I have better interpretion quality on the strength of soft clay in Hangzhou Bay offshore area. The established correlations are not only suitable for the muddy silty clay

but also for the muddy clay and silty clay

which have good site applicability.