ISSN: 0149-6115
Page Count: 12

Analysis of Bender Element Tests

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

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

Riemer, MF
Adjunct assistant professor,University of California,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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