Predicting the physico-mechanical properties of Konya pyroclastic rocks from the needle penetration index

Well-prepared core samples suggested by standards for the laboratory tests cannot be prepared usually particularly from soft and clay-bearing rocks. For this reason, the needle penetration test was developed for the estimation of properties of soft rocks. This study investigates the predictability of physico-mechanical properties of pyroclastic rocks from the needle penetration index. The needle penetration, the uniaxial compressive, density, and porosity tests were carried out on the pyroclastic rocks from Konya region. The needle penetration index values were correlated to the physico-mechanical properties. Good correlations were obtained between the needle penetration index and both compressive strength and density. However, the correlation between the needle penetration index and porosity is weak. It was concluded that the compressive strength and density of Konya pyroclastics could be predicted from the needle penetration index. The correlation between the needle penetration index and porosity should be further investigated for Konya pyroclastics.