ISSN: 1945-7545
CODEN: GTJODJ
Page Count: 12

Analysis of Bender Element Tests

Arulnathan, R
Graduate student and assistant professor, University of California, Davis, CA

Boulanger, RW
Graduate student and assistant professor, University of California, Davis, CA

Riemer, MF
Adjunct assistant professor, University of California, Berkeley, CA

Abstract

A study is presented of potential errors in, and methods of interpreting, the results of cantilever-type, piezoceramic bender element tests for measuring the shear wave velocity of laboratory soil specimens. Interpretations based on the first direct arrival in the output signal are often masked by near-field effects and may be difficult to define reliably. Interpretations based on characteristic points or cross-correlation between the input and output signals are shown to be theoretically incorrect in most cases because of: (1) the effects of wave interference at the boundaries; (2) the phase lag between the physical wave forms and the measured electrical signals; and (3) non-one-dimensional wave travel and near-field effects. Interpretations based on the second arrival in the output signal are theoretically subject to errors from non-one-dimensional wave travel and near-field effects. Differences in V_s values obtained by the different interpretation methods are illustrated analytically and experimentally.

Keywords:
shear modulus, shear wave velocity, bender element, triaxial test

Paper ID: GTJ10750J
DOI: 10.1520/GTJ10750J
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