SHEAR WAVE VELOCITY AND FREQUENCY DEPANDENCY OF TIDAL FLAT SEDIMENTS IN JIAOZHOU BAY

Shear wave velocity is the important factor in seafloor acoustics, and the essential parameter in marine engineering geological exploration, which has close relationship with sediment physical properties. Samples were collected from Jiaozhou Bay to conduct shear wave velocity measurement by bender element system, and construct the correlation between shear wave velocity and frequency dispersion and physical parameters. Results present that shear wave velocity ranges from 26.5 to 103.5ms-1 at the frequency from 250Hz to 2000Hz; sandy sediment was characterized by the maximum shear wave velocity, silty sediment took second place, and clayed sediment and silty clay sediment has the low shear wave velocity; obvious frequency dispersion is found at the measuring frequency of shear wave velocity, and logarithmic growth function can describe the relationship between shear wave velocity and measuring frequency; dispersion factor ranges from 0.3 to 31.1, and PFE(percent frequency effect) ranges from 1.1%to 103.8%, which is affected by sediment types; hypo-two function can describe the relationship between shear wave velocity, dispersion factor, PFE and sediment physical parameters with different correlation degree but consistent variation trend; comparatively speaking, it is obvious low for the correlation degree between PFE and sediment physical parameters.