The deformation behavior of Tage Tuff during desiccation was investigated. Strain as well as compressional (P) and shear (S) wave velocities were measured concurrently in a set of cylindrical Tage Tuff specimens cored across and along the bedding plane. Two saturated specimens were prepared in one-dimensional drying conditions (50°C, 50% relative humidity) at a time. The strain and weight of one specimen was automatically measured using strain rosettes and an electronic scale. The ultrasonic wave velocity and weight of the second specimen were measured using transducers and an electronic scale and manually recorded.
When the degree of saturation decreased by no more than 70%, P wave velocity decreased with two distinct trends depending on the two main textural directions. However, S wave velocity and strain remained constant. This was due to the inter-bedding and intra-bedding pore water characteristics within the specimen. When the saturations dropped below 30%, both velocities increased with a decrease in strains due to the desiccation-driven hardening. The relationship of incremental P wave velocity and incremental volumetric strain followed the shape of a parabola which can explain by the theories of linear poroelasticity. Different height specimens (5cm and 3cm) exhibit similar strain magnitude and wave velocity behavior.
