New tool for shear wave velocity measurements in model tests

A method for measuring the shear wave velocity (Vs) of soil in a centrifuge model using a "mini-air hammer" is presented. Propagation of shear waves in a model soil profile was recorded in-flight by a vertical array of four accelerometers placed at different depths. Shear wave velocities were measured at different centrifugal accelerations for Nevada sand and for peaty organic soil. The V-s measured in the centrifuge was in excellent agreement with the V-s measured using piezo-ceramic bender element tests on these soils in a triaxial device. The value of the V-s measurements is demonstrated by typical analysis results for a centrifuge model of horizontally layered peaty organic soil and Nevada sand subjected to simulated earthquake shaking. Site response analyses using the measured shear wave velocities as input parameters produced good agreement with the measured site response.