Mechanical properties and failure behavior of rock with different flaw inclinations under coupled static and dynamic loa
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Mechanical properties and failure behavior of rock with different flaw inclinations under coupled static and dynamic loads XIAO Peng(肖鹏)1, LI Di-yuan(李地元)1, ZHAO Guo-yan(赵国彦)1, ZHU Quan-qi(朱泉企)1, LIU Huan-xin(刘焕新)2, ZHANG Chun-shun(张春顺)3 1. School of Resources and Safety Engineering, Central South University, Changsha 410083, China; 2. Deep Mining Laboratory of Shandong Gold Group, Laizhou 261442, China; 3. Department of Civil Engineering, Monash University, Clayton, VIC 3800, Australia © Central South University Press and Springer-Verlag GmbH Germany, part of Springer Nature 2020 Abstract: The deep fissured rock mass is affected by coupled effects of initial ground stress and external dynamic disturbance. In order to study the effect of internal flaw on pre-stressed rock mechanical responses and failure behavior under impact loading, intact granite specimens and specimens with different flaw inclinations are tested by a modified split Hopkinson pressure bar (SHPB) and digital image correlation (DIC) method. The results show that peak strain and dynamic strength of intact specimens and specimens with different flaw angles (α) decrease with the increase of axial static pressure. The 90° flaw has weak reduction effect on peak strain, dynamic strength and combined strength, while 45° and 0° flaws have remarkable reduction effect. Specimens with 90° flaw are suffered combined shear and tensile failure under middle and low axial static pre-stresses, and suffered shear failure under high axial static pre-stresses. Specimens with 45° and 0° flaws are suffered oblique shear failure caused by pre-existing flaw under different axial static pre-stresses. Besides, based on digital image correlation method, it is found that micro-cracks before formation of macro fractures (include shear and tensile fractures) belong to tensile cracks. Tensile and shear strain localizations at pre-existing flaw tip for specimen with 45° and 0° flaws are produced much earlier than that at other positions. Key words: split Hopkinson pressure bar (SHPB) system; digital image correlation (DIC); coupled static and dynamic loads; flaw; crack propagation Cite this article as: XIAO Peng, LI Di-yuan, ZHAO Guo-yan, ZHU Quan-qi, LIU Huan-xin, ZHANG Chun-shun. Mechanical properties and failure behavior of rock with different flaw inclinations under coupled static and dynamic loads [J]. Journal of Central South University, 2020, 27(10): 2945−2958. DOI: https://doi.org/10.1007/s11771-0204520-x.
1 Introduction With development of industrial technology and consumption of surface resources, human beings are increasingly exploiting underground resources. The deep underground engineering such as tunnels and hydro power stations is subjected to high ground stress, and often subjected to dynamic loads
such as mechanical disturbance and blasting. Stability of deep engineering has always been a concern, which is closely related to work environment of underground workers and equipments. It is found that rock masses at depth have different failure phenomena with shallow
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