MEASUREMENT OF SHEAR-WAVES IN LABORATORY SPECIMENS BY MEANS OF PIEZOELECTRIC TRANSDUCERS

The use of piezoelectric ceramics to measure shear wave velocity in la boratory soil specimens is discussed. The experimental technique and i nterpretative methodology are described. Both bender and flat-plate ce ramic elements were employed and each performed well. Interpretation o f the shear waveforms generated with each transducer improved as the n umber of wavelengths between the source and receiver increased with fo ur or five wavelengths being optimum. Shear wave velocities measured u sing both types of transducers compared closely with the results of a parallel program performed with the torsional resonant column. Based o n this work, flat-plate shear transducers show significant potential f or future laboratory use because of their robustness and noninvasive n ature.