Numerical studies of dynamic properties and cracking behavior of sandstone with randomly distributed flaws subjected to dynamic loading

Underground engineering construction or mining activities are increasingly developed to deeper. The ground stress affects not only dynamic response but also the cracking behaviors of rocks. The dynamic crack process investigation in different rocks with one or two flaws has been extensively studied. In the present study, the investigation of natural flawed rock extended to many randomly distributed flaws, which are then subjected to different ground stresses. Three kinds of flaw distribution are created. These dynamic tests are performed by a numerical Split Hopkinson Pressure Bar setup. Firstly, the strength and deformation characteristics of these sandstone specimens are investigated and compared under these confined stresses. Secondly, the cracking processes of sandstone are studied, which are divided into three stages-quickly, slowly deteriorated and stable stage. Thirdly, the dynamic failure patterns of these specimens are systematically analyzed. The numerical results show that the specimens with different flaw distribution have different failure modes. And also, they are affected by the confinements. Finally, the influence of confined stress and flaw geometric parameter on the cracking behaviors of flawed sandstone are discussed.