Influence of rock properties on thrust and torque during rock coring operations a case study

Abstract

The most important parameters for rock strength evaluations in excavation, mining, and mechanical engineering projects are the uniaxial compressive strength, Brazilian tensile strength, density, abrasivity, and impact strength index. To estimate these parameters, several laboratory investigations and nondestructive methods were proposed. The possibility of using time-saving models for predicting uniaxial compressive strength (UCS), Brazilian tensile strength (BTS), density, abrasivity, and impact strength index was investigated because of the difficulties in core specimen preparation. The novelty of this investigation was the prediction of rock properties using thrust and torque generated during rock coring operations. For this purpose, drilling experiments were conducted on seven different types of rock samples using a computer numerical control drilling machine. Based on the statistical analysis, simple linear regression equations were proposed for estimating rock properties, such as compressive strength, tensile strength, density, abrasivity, and impact strength index. The coefficient of determination (R 2), values obtained for thrust are 90.8, 93.3, 80.7, 87.6, and 96.3%, for compressive strength, tensile strength, density, abrasivity, and impact strength index, respectively. Whereas the corresponding torque values are 84.9, 83.9, 95.9, 81.6, and 82.6%. The developed models can be used in the exploration and excavation developments for the prediction of rock properties.