Investigation of the geomechanical properties of magmatic origin rocks in Gümüşhane province

In this study, investigation of the geomechanical properties of magmatic origin rocks in the Gümüşhane province and empirical relations between these properties were investigated. For this purpose, 30 block samples from different areas whose approximate sizes are 20x30x40cm were collected; test specimens from these samples were prepared in accordance with ISRM suggested methods, the tests to determine the index, mechanical and elastic properties were done. Petrographical investigations were carried out on the 33 samples. As a result of the petrographical assessments, the quartz 30-37.30 %, orthoclase 30-36.60 %, plagioclase 18.20-25 %, mafic mineral 6-12 % were determined in rocks called as monzogranite. However, modal analysis was not able to be done in the andesites. At the end of the experimental studies, it was determined that in the andesites unit volume weight values vary between 24.37-25.73 kN/m3, water absorption by weight values between 0.78-1.86 %, water absorption by volume values between 2.02-4.77 %. As for granites, it was determined that unit volume weight values vary between 25.45-25.97 kN/m3, water absorption by weight values between 0.24-0.96%, water absorption by volume values between 0.63-2.50 %. In addition to this, in andesites P wave velocity for the saturated conditions varies between 3961-5451 m/sec and S wave velocity between 2171-3310 m/sec while in granites P wave velocity ranges between 3850-5812 m/sec and S wave velocity between 2151-3115 m/sec. It is determined that while in andesites in dry conditions P wave velocity varies between 3669-5462 m/sec and S wave velocity between 2205-3011 m/sec, in granites P wave velocity varies between 2857-5251 m/sec and S wave velocity between 1793-2904 m/sec. In andesites, the uniaxial compressive stregth values varied between 54.09-214.36 MPa, modulus of elasticity 19.80-53.16 GPa and Poisson's ratio value 0.11-0.46; as for granites the uniaxial compressive strength value varied between 24.60-140.15 MPa, modulus of elasticity 22.22-76.92 GPa and Poisson's ratio value 0.03-0.50. As a result of the statistical assessments, the highest correlation coefficient values which are 0.90 in andesites and 0.94 in granites were obtained from the data of the P and S wave velocity measurements. The lowest correlation coefficient values were determined between quartz/alkaline feldspar ratio and porosity in granites. Especially, equations which are statistically meaningful and have high correlation coefficient value can be used to determine indirect predictions of related parameters.