Small‐Strain Elastic Properties of Compacted Clayey Soils During Drying

In this study ultrasonic methods were used for the determination of small-strain elastic properties of compacted clayey soils. Three clayey soils compacted at different moisture contents and compactive efforts were tested while drying. Piezoelectric transducers were used to generate and receive Pand Swaves on cubical soil samples with oblique corner cuts. Five elastic parameters of cross-anisotropy were calculated using three P-wave and two S-wave velocity measurements. Constrained, Young's, and shear moduli in the vertical and horizontal directions increased during drying. Young's and shear moduli increased monotonically, while constrained modulus exhibited a peak for wet of optimum and optimum water content samples. It was observed that Poisson's ratios decreased during drying and that the soils compacted with high compactive effort had lower Poisson's ratios compared to the soils compacted with low compactive effort at the same saturation level. Anisotropy value, n, increased for wet of optimum and optimum water content samples during drying, which was attributed to particle reorientation during shrinkage process. On the other hand, n did not change significantly for soils compacted at dry of optimum water content.