Correlation Between Brazilian Test And Unconfined Compressive Strength Test Results For Different Types Of Iraqi Rocks

Abstract

The present study aims to develop a relationship between the indirect Brazilian tensile stress (BTS) and the uniaxial compressive stress (UCS)  of different types of northern Iraqi rocks. A series of experimental works was carried out on different samples taken from different zones northern Iraq.  120 samples of intact rocks were prepared and tested by compressive test machine and Brazilian test apparatus. Three types of rock samples (Sandstone, Claystone, and Limestone) were taken from different zones northern Iraq (Domeez, Baadra, and Zawita). Two types of destructive tests were carried out on intact rock sample (uniaxial compressive and Brazilian test). The mean values of uniaxial compressive stress results varied between 47.5 and 81.5 and the mean values Brazilian test results varied between 4.12 and 8.15 MPa for Sandstone, Claystone, and Limestone, respectively. Unconfined compressive strength was also correlated to Brazilian tensile stress. New equations for correlations were proposed relating between the uniaxial compressive stress and Brazilian test results for the three types of rocks and indirect Brazilian test which provides a good predictor of unconfined compressive strength.