Estimating the pre- failure points for rocks during laboratory testing is not a trivial task. In this study, a new approach is introduced that utilizes change in the slope of the load-deformation curves of rock in the loading cycle for marking the onset of failure point during uniaxial test of a given rock. At each step, load-deformation data footprints of the rock under test are inspected and a decision is made whether the failure has started or not. The load-deformation data obtained from different tests of different rocks are examined including; Norite, Granite, Limestone, Sandstone, Siltstone and Marble. The computational results over 154 cored rock samples show that the proposed approach locates the onset of failure point for a given rock with an acceptable degree of accuracy., Deniz Mamurekli., and Obsahuje bibliografii