Effects of serpentinization degree on the geotechnical characteristics of ultramafic rocks in the southwest of Mashhad city (Iran)

The present work was conducted to investigate the geotechnical properties of two meta-peridotites and meta-pyroxenites of an ultramafic complex mainly consisting of ultramafic rocks. For this purpose, microscopic studies were performed to determine the percentage of serpentinization in these rocks. In addition, a number of mechanical and physical tests were performed on collected samples with different serpentinization grades to determine their geotechnical properties. Finally, the serpentinization degree and geotechnical results were compared for meta-peridotites and meta-pyroxenites. The results revealed a closed relationship among the serpentinization degree, Brazilian tensile strength (BTS), uniaxial compressive strength (UCS), and density. Due to the high costs of the UCS test, this study attempts to establish a relationship between these parameters. To demonstrate the relationship between these parameters, the obtained results are presented as a single graph. So, the UCS can be estimated based on the BTS, density, and the serpentinization degree. The results showed that the field behavior of rock masses also could be used to predict the UCS) range and degree of serpentinization. Overall, these results can be useful for determining the geotechnical properties of these rocks.