INVESTIGATION OF THE RELATIONSHIP BETWEEN UNIAXIAL COMPRESSIVE STRENGTH VALUES AND POINT LOAD INDEX VALUES OF HASANDAĞ VOLCANICS

When suitable and standardized rock samples are not able to be prepared, then, the uniaxial compressive strength of that samples will not be obtained directly. In order to eliminate this kind of rock-related deficiencies, some techniques, which are used in both laboratory and field with some mobilized instruments, have been improved. One of them is the point load index test.In order to indirectly determine the compressive and tensile strength parameters of rocks from the point load index values, when the experimental studies compiled from the literature are examined, it is seen that the definition of a standard “k” value for all rocks is incorrect and it would be more accurate to develop rock- or site-based correlations instead of such generalizations. Within the scope of this evaluation; Hasandağ Volcanics, located in the Nevşehir province volcanic succession, were investigated in our study in order to define the mechanical properties of a locally widespread formation and to determine the strength parameters of low-medium strength ignimbrite and tuff volcanic rocks. Here, using NX (54 mm) diameter core samples with a length-to-diameter ratio of 1 and 2.5, uniaxial compressive strength valuesdetermined by considering orientations in dry and saturated conditions, and point load strength tests performed in both dry and water-saturated conditions, high correlation values were obtained by comparing the results found after d₅₀ equivalent core diameter correction.