Shear Wave Velocity Profiles in Offshore Soils Using the Field Velocity Probe

摘要

Shear wave velocity has been commonly used as one of the importantdesign parameters for geotechnical structures which are subjected todynamic loading. This paper introduces the development andapplication of a new apparatus, the Field Velocity Probe (FVP) formeasurement of shear wave velocity in the field. The shape of the FVPis a blade with two frames, with transducers installed at the tip of theframes. The shear wave velocity is the ratio of the travel distance to thetravel time of the shear waves. Thus, no inversion process is required.Penetration tests have been carried out to assess the applicability anddisturbance effects in a calibration chamber. In calibration chambertests, reconstituted clay is mixed with water using a slurry mixer tocompose a model soil with a water content of 110 %. Afterconsolidation of the reconstituted clay, FVP, downhole, and crossholevelocity tests are carried out at 1cm intervals during penetration of thepenetrometers. The comparison tests produced similar shear wavevelocity profiles for each of the apparatus. Shear wave velocitymeasurements in the field are measured every 10cm in clay soils up to30 m by the FVP. The field tests show that the FVP produces a detailedshear wave velocity profile in clay. This study suggests that FVP maybe an effective device for measuring the shear wave velocity withminimized disturbance in soft clay.