Experimental and numerical studies on dynamic compression failure characteristics of granite under real-time temperatures

To investigate the thermodynamic properties of biotite granite, the mechanical response and failure process of the rock samples under different real-time temperatures (20℃, 100℃ and 200℃) are analyzed based on the laboratory tests and numerical simulations. The results show that the compression strength and elastic modulus of the granite sample are the largest at the temperature of 20℃ and the lowest at 100℃. The fracturing degree of the sample at 100℃ is more obvious than that at 20℃ and 200℃. As the loading rate rises, the peak strength and peak strain of the stress-strain curve increase along with the crack evolution and failure degree. At a low loading rate, the microcracks in the peripheral area of the sample are firstly initiated. The internal microcracks of the sample can be activated even at the initial stage of loading with the increase of loading rate. In addition, the proposed method for determining the Holmquist-Johnson-Cook (HJC) model parameters is proved to be feasible and accurate. The numerical simulation can well reflect the mechanical characteristics of the rock sample under the coupling action of impact loading and real-time temperatures, and the failure mode and rupture process of the sample during dynamic compression can be also illustrated realistically using the coupled HJC model and related failure criterion. © 2019, Editorial Office of Chinese Journal of Geotechnical Engineering. All right reserved.