Correlation Between the Shear Strength Parameters of Clastic and Carbonate Rocks with the Brazilian Tensile Strength and the Uniaxial Compressive Strength

The objective of the current study is to investigate the relation between the Brazilian tensile strength (BTS) and the uniaxial compressive strength (UCS) with the shear strength parameters (cohesion and internal friction angle) of some clastic and carbonate rocks from the southern part of the East Attica Prefecture, Greece. For this reason, several specimens were prepared and tested for the direct evaluation of BTS, UCS, and the shear strength parameters of four rock types comprising marbles, limestones, sandstones, and breccias. Applying simple linear regression techniques to the results, it was found that a strong correlation exists between cohesion with BTS or UCS values, for the studied clastic and the carbonate rocks. On the other hand, the values of the angle of internal friction seem to have no meaningful statistical correlation with BTS or UCS values. Therefore, a different linear model is used for the correlation of internal friction angle values, considering the ratio between the uniaxial compressive strength with the Brazilian tensile strength.