The design and set up of a system to measure the travel time of shear waves in Bío Bío sand samples using bender elements, is described. An oedometer device was adapted to install bender elements. Measurements were carried out for sand samples with different relative density, pressure/deformation, diameter/height, dry/saturated and varying the frequency, amplitude and type of the triggered electric signals. Repetitiveness and calibration were evaluated. Travel times are evaluated using criteria in the time and frequency domain. From the theory of elasticity, results are interpreted as shear wave velocity and elastic shear modulus as a function of vertical effective stress, void ratio and vertical deformation. The shear wave velocity and shear modulus increased with relative density and effective vertical stress as found previously by other authors. Finally, well known formulae for estimating the elastic shear modulus are used to compare with the experimental results. The estimations were good for effective vertical stresses around 100 kPa, but underestimation and overestimation of the shear modulus occurred for stresses below and above that value, respectively. Soil stiffness during unloading/reloading cycles was underestimated with the expressions used for loading.
IOS Press, Inc.
6751 Tepper Drive
Clifton, VA 20124
Tel.: +1 703 830 6300
Fax: +1 703 830 2300 firstname.lastname@example.org
(Corporate matters and books only) IOS Press c/o Accucoms US, Inc.
For North America Sales and Customer Service
West Point Commons
Lansdale PA 19446
Tel.: +1 866 855 8967
Fax: +1 215 660 5042 email@example.com