Measurement of G_max and estimation of K₀ of saturated clay using bender elements in an oedometer

Recent developments in bender element technique have made it possible to determine G_max and estimate K₀ of soils under complex loading conditions. By measuring the shear wave velocities in different shear planes, the cross anisotropy in G_max of soil induced by axial-symmetric loading can also be determined. The shear wave velocities can also be used to estimate the horizontal earth pressure coefficient at rest K₀. This paper reports on an experimental setup that uses bender elements installed in an oedometer to measure shear wave velocities in four shear planes of a saturated clay specimen under different consolidation pressures. The data is used to investigate the cross anisotropy of stiffness in clay due to a K₀ stress condition. The measured G_max is compared with the results from a commonly used empirical formula. The measured shear wave velocities on different shear planes are also used to calculate K₀ of clay under different consolidation pressures and compared with results from empirical formulae. The applied stress condition includes loading, unloading, and reloading of up to 22 cycles, thus providing information to study the influence of repeated loading on G_max and K₀ of a saturated clay.