Experimental Study For Testing Rock Dynamic Fracture Toughness Under The Loading Of Split Hopkinson Pressure Bar

Rock is a typical quasi-brittle, flaws material, and its failure in nature is flawing and micro crack propagating and coalescing dynamic process. The rock dynamic mechanical properties are more important than before in the thought of safe to producing, living and developing of explosion and mining engineering. Facture toughness as the estimating parameter to the ability of flaw material resists its micro cracks propagation is accepted by more and more by rock and civil engineers in and out-borders. International Society for Rock Mechanics (ISRM) suggested two type specimens in testing mode I static fracture toughness for rock—chevron bend (CB) specimen and short rod (SR) specimen in 1988, and later, the ISRM suggested another specimen again in testing mode I static fracture toughness for rock— cracked chevron notched Brazilian disc (CCNBD) in 1995. But ISRM has no suggestion of rock dynamic fracture toughness testing specimen and its method.The emphases of this paper are settled on rock mode I dynamic initiating fracture toughness experimental test. First, as the convenience of specimen making and loading, a successful rock static fracture toughness experimental testing specimen—edge notched disc and its testing method are extended to dynamic situation, and the dynamic initiating fracture toughness values are successful gotten with the high speed loading apparatus of large diameter split Hopkinson pressure bar; and the apparatus loading effect is analyzed. Second, a plane-strain mode I dynamic fracture toughness experimental testing specimen— rectangular double beam for rock is presented according to the K_I test standard rectangular cracked chevron notched...