Sample diameter effects on the relationships between index properties and P-wave velocities of carbonate rock in different environments

This study intended to investigate and discuss the effect of sample diameter on the relationships between index properties and P-wave velocities of carbonate rock in natural, dry, and saturated environmental conditions using the complete experimental data. From representative limestone rock blocks, 190 core samples with five different diameters and various lengths were prepared. Based on the ASTM and ISRM standards, the UPV and index tests such as density (ρ), unit weight (γ), specific gravity (G_s), water absorption (w_c), and porosity (n) were performed on the prepared core samples. The results showed the relationships between index properties; natural, dry, and saturated densities (ρ_n, ρ_d, and ρ_s) and unit weights (γ_n, γ_d, and γ_s), specific gravity (G_s), water absorption (w_c), and porosity (n) and natural, dry, and saturated P-wave velocities (Vⁿ_p, V^d_p, V^s_p) of limestone indicated increasing or decreasing trend with respect to five different core sample diameters. The study revealed that the effects of different sample diameters on the relationships between index properties; ρ_n, ρ_d, ρ_s, γ_n, γ_d, γ_s, G_s, w_c, n, and Vⁿ_p, V^d_p, V^s_p of were limited because all best-fit lines were located in a narrow band. Furthermore, the purposed empirical equations were validated using t- and F-tests that indicated a strong relationship between the P-wave velocities (Vⁿ_p, V^d_p, V^s_p) and the densities (ρ_n, ρ_d, and ρ_s), unit weights (γ_n, γ_d, and γ_s), G_s, w_c, and n of limestone. This study showed that the index properties of intact limestone could be used to estimate P-wave velocities (Vⁿ_p, V^d_p, V^s_p).