Volume 36, Issue 2 (March 2013)
Experimental Study Investigating the Effects of Setup Conditions on Bender Element Velocity Results
An experimental program was conducted in order to establish the dominant factors that affect the interpretation of the small strain shear modulus of soils when using bender elements. Both Ticino sand and resedimented Boston blue clay (RBBC) were used to develop the characteristics of the bender element behavior and to isolate the parameters that most closely need to be monitored during the experimental procedure. After the experimental program was completed, a comparison with published results was performed as a secondary measure of reliability of the measurements. The conclusion of this investigation showed that the signals produced by the bender elements can be substantially improved if the wavelength ratio and aspect ratio are maintained in an acceptable range of greater than two and less than one, respectively. Furthermore, after conducting an extensive series of ray path analyses and varying the confining material of the specimen, it was clear that the geometry of the bender element was the cause of major discrepancies between velocity results, which was caused by the creation of not only side traveling P-waves in addition to the orthogonally propagating S-wave, but also directly traveling P-waves.