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The present work aims to understand the stress–strain response of an igneous rock, granite, under high loading rate through detailed experimental and numerical analyses. The high-strain-rate characterization of granite rock was performed for two different diameters and five different slenderness ratios of the rock specimens using a 76-mm-diameter split Hopkinson pressure bar (SHPB) device in an effort to determine the appropriate specimen dimension for granite to be used in an SHPB test. The stress–strain response of the rock specimens was studied by systematically varying the length of the striker bars and the gas gun pressure values of the SHPB device. The petrological and static characterization of the granite rock was also carried out to assess the response of the rock specimens. Finally, a methodology was proposed to characterize granite rock specimens under high loading rate. Further, a numerical simulation of the SHPB test on granite rock was performed using the strain rate–dependent Johnson-Holmquist 2 (JH-2) model available in the finite-element software LS-DYNA. The simulation results were compared with the experimental data; thus, the parameters of the JH-2 model for granite rock were determined. The determined parameters were then used in blast analysis of a tunnel subjected to 20-kg TNT explosive. [ABSTRACT FROM AUTHOR]

In the present work, dynamic stress–strain response of five sedimentary and three metamorphic rocks from different regions of India, e.g. Kota sandstone, Dholpur sandstone, Kota limestone, Himalayan limestone, dolomite, quartzite, quartzitic gneiss and phyllite have been investigated through split Hopkinson pressure bar test at different strain rates. The dry density, specific gravity, static compressive strength and tensile strength values of the rocks have also been determined. Petrological studies of the rocks have been carried out through X-ray diffraction test and scanning electron microscope test. It is observed from the stress–strain response of the rocks that the peak stress increases with increasing strain rate. Dynamic increase factors for the strength of these rocks have been determined by comparing the dynamic and the static peak compressive stresses and correlation equations are proposed. [ABSTRACT FROM AUTHOR]

This paper presents the static and dynamic experimental characterization of dolomite subjected to static unconfined compressive strength test and dynamic split Hopkinson pressure bar (SHPB) tests. The dynamic compression tests on rock samples are performed at strain rates from 500/sec to 1500/sec. It is observed from the results that the rocks exhibit significant strain rate sensitive behaviour and the peak stress increases with increasing strain rate. In the present work, the force equilibrium at the incident and transmission bar ends of the rock samples has been studied. Dynamic increase factor ( DIF ), i.e. the ratio of the dynamic to static peak stress has been calculated at different strain rates. Based on the calculated DIF values, an empirical correlation equation has been proposed for the DIF of the rock with the strain rate induced. [ABSTRACT FROM AUTHOR]