The dynamic shear modulus ratio and damping ratio of soil are indispensability for seismic safety evaluation and soil layer seismic response analysis of engineering sites. In this paper

using the apparatus and method of stress-controlled cyclic triaxial test

an experimental study on dynamic shear modulus ratio and damping ratio for the soils of Bohai seafloor is performed. The test apparatus is HX100 cyclic triaxial test system. The soil samples

including clay

silty clay

fine sand

silty sand

silty fine sand

sampled from QK18-2

BZ13-1 and BZ26-2 oilfields of Bohai sea. The relations of G/Gmax-γ and λ-γ are fitted by two hyperbolic equations

and the curves and recommended values of G/Gmax-γ and λ-γ for each soil are obtained. These results have been used in the seismic safety evaluation of these oil platforms and also have an important reference for other engineering constructions in the sea area. Furthermore

the results of the paper can provide the related basic data and work method for a future seismic zoning of Chinese sea area.