Correlation between Uniaxial Compressive Strength and Point Load Index for Salt-Range Rocks

M. Akram, M. Z. A. Bakar


Nine rock types including Sandstone, Limestone, Siltstone, Dolomite and Marl collected from six different rock formations of the Salt Range area of Pakistan were tested to evaluate the correlations between the uniaxial compressive strength and the corresponding values of the point load index. Two hundred rock cores were drilled and used for the uniaxial compressive strength and point load index tests. Results indicate the existence of two rock groups showing distinct behaviour in the context of this correlation. The first group of rocks, Group A, consists of hard Jutana Sandstone, Baghanwala Sandstone, Siltstone, Sakessar Massive Limestone, Khewra Sandstone and Dolomite. The second group of rocks, Group B, consists of relatively soft Dandot Sandstone, Sakessar Nodular Limestone and Marl. The correlation equations for predicting compressive strength using point load index for each group are presented along with their confidence limits to show the variability of results produced from each equation.

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