Size Factor in Handheld P-Wave Velocimetry in Rocks

Abstract

P-wave velocity is a non-destructive test (NDT) used directly and indirectly in different disciplines. In recent years, portable equipment that can indirectly ascertain P-wave velocity has gained popularity for in situ measurements across multiple disciplines, including archeology, geology, and civil engineering. As the sample size effect has not been previously researched for portable indirect P-wave velocity (VPI) measurement devices, this study researched the size-factor effect in magmatic rocks commonly used as building stones. Within this scope, 684 prism samples with 2 & times; 2, 3 & times; 3, 4 & times; 4, 5 & times; 5, 6 & times; 6, and 7 & times; 7 cm2 square basal area and height of 17 cm, and 190 (38 & times; 5) cube samples with a side length of 7 cm were prepared from 38 different rocks (plutonic, volcanic, pyroclastic, and sedimentary). The variations in indirect P-wave velocity (VPI) were experimentally determined on prismatic samples with different base areas. According to the results, the optimum sample cross-sectional area where the indirect P-wave velocity value did not change was determined to be 6 & times; 6 cm2. Furthermore, the direct P-wave velocity (VPD) values of the rocks were determined using cubic samples. The simple regression relationship between VPD and VPI measurements was investigated, and a very strong positive linear correlation (R2 = 0.966) was identified.