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