Experimental Determination of the Mechanical Properties and Deformation Constants of Mórágy Granitic Rock Formation (Hungary)

Determination of the mechanical behaviour of intact rock is one of the most important parts of any engineering projects in the field of rock mechanics. The most important mechanical parameters required to understand the quality of intact rock are Young’s modulus ( E ), Poisson’s ratio ( ν ), the strength of rock ( σ c ) and the ratio of Young’s modulus to the strength of rock known as modulus ratio ( M R ), which can be used for calculations. The particular interest of this paper is to investigate the relationship between these parameters for Hungarian granitic rock samples. To fulfil this aim, Modulus of elasticity ( E ), Modulus of rigidity ( G ), Bulk modulus ( K ) and the modulus ratio ( M R = E / σ c ) of 50 granitic rock samples collected from Bátaapáti radioactive waste repository were examined. Fifty high-precision uniaxial compressive tests were conducted on strong ( σ c > 100 MPa) rock samples, exhibiting the wide range of elastic modulus ( E = 57.425–88.937 GPa), uniaxial compressive strength ( σ c = 133.34–213.04 MPa) and Poisson’s ratio ( ν = 0.18–0.32). The observed value ( M R = 326–597) and mean value of M R = 439.4 are compared with the results of similar previous researches. Moreover, the statistical analysis for all studied rocks was performed and the relationship between M R and other mechanical parameters such as maximum axial strain ( ε a, max ) for studied rock samples was discussed. Finally, the validity of the proposed mathematical model by Palchik (Geomech Geophys Geo-energy Geo-resour 6:1–12, 2019 ) for stress–strain behaviour of granitic rock samples was investigated.