Laboratory measurements of small strain properties of dry sands by bender element

The S-wave and P-wave velocities in dry sands are simultaneously measured by a single pair of bender elements (BE) incorporated into a standard resonant column (RC) apparatus with a torsional shear (TS) function. The small strain properties, including shear modulus Go, constrained modulus M-0 and Poisson's ratio v, are determined for specimens at various densities and confining pressures. The results show that the Go values obtained from the BE tests agree well with those from RC and TS tests, indicating the reliability of the signal interpretation and the testing system. Furthermore, the Go data of the present test series is in good agreement with the data from the literature. The results also show that Go increases faster than M-0 as the soil density and the confining pressure increase. In terms of Poisson's ratio, it decreases with an increasing soil density and confining pressure and generally lies in the range of 0.18-0.32 for the tested sands. Empirical equations are established to approximately estimate Poisson's ratio from the measured Go or M-0 values. (C) 2013 The Japanese Geotechnical Society. Production and hosting by Elsevier B.V. All rights reserved.