An investigation on ultrasonic wave velocity of laminated sandstone under freeze-thaw and salt crystallization cycles: Insights from anisotropy effects

In this study, the anisotropy effects on the P (Vp) and S (Vs) wave velocities are investigated in laminated sandstone subjected to freeze-thaw (FT) and salt crystallization (SC) processes. For this purpose, cylindrical core specimens were prepared from sandstone at angles (beta) of 0 degrees, 30 degrees, 45 degrees, 60 degrees, and 90 degrees to the lamination direction. Next, FT and SC tests were performed up to 60 cycles. After every 10 cycles, the specimens' Vp and Vs were determined at various beta values. The decay constant (lambda), half-life (N-1/2), and rate of loss (RL) were used to investigate the anisotropy effects on the Vp and Vs of specimens under FT and SC and compare the effects of FT and SC on the Vp and Vs. The results indicated that anisotropy is an important factor in the durability of the specimens against FT and SC. In this respect, the specimens with beta = 0 degrees and beta = 60 degrees had the least and the highest changes in the Vp and Vs, respectively. Also, it was found that the anisotropic behavior of the specimens is different at various cycles of FT and SC such that it is intensified at higher cycles. Overall, it was concluded that SC had more significant effects on the Vp and Vs compared to FT. Considering the beta values, the effect of a single cycle of the SC test in decreasing the Vp and Vs of the specimens corresponds to 1.34 to 1.94 and 1.28 to 1.70 cycles of the FT test, respectively.

Automated summary

This study investigates the anisotropy effects on the P (Vp) and S (Vs) wave velocities in laminated sandstone subjected to freeze-thaw (FT) and salt crystallization (SC) processes. The results indicate that anisotropy is an important factor in the durability of the specimens against FT and SC, with the least and the highest changes in Vp and Vs observed in specimens with beta = 0 degrees and beta = 60 degrees, respectively. Additionally, it is found that the anisotropic behavior is intensified at higher cycles of FT and SC. Overall, SC has more significant effects on Vp and Vs compared to FT, with the effect of a single cycle of the SC test corresponding to 1.34 to 1.94 and 1.28 to 1.70 cycles of the FT test in decreasing Vp and Vs, respectively.