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为了考察圆盘试件不同中心孔径对岩石动态断裂韧度测试值的影响,采用直径80 mm含有不同中心圆孔孔径的圆孔裂缝平台巴西圆盘试件,在Hopkinson压杆系统上进行径向冲击试验,获得岩石的动态断裂韧度。结果表明,当中心圆孔孔径与圆盘直径之比r0/R∈(0.10,0.30)时,岩石动态断裂韧度的平均值为4.57 MPa·m1/2,测试值受中心圆孔孔径变化的影响并不明显。试件的断裂模式有一定差异,当圆孔孔径较小时,在主裂纹扩展的过程中萌生较多的次生裂纹;随着孔径的增大,次生裂纹减少,试件呈现更加明显的宏观拉贯通破坏。对于推广中心圆孔裂缝平台巴西圆盘测试岩石动态断裂韧度的方法,以及掌握岩石受到动态冲击时的破坏特性具有重要的意义。
In order to investigate the influence of different central aperture of disk specimen on the dynamic fracture toughness test of rock, a Brazilian disk specimen with a hole with a diameter of 80 mm and a hole center with different center hole diameters was used to measure the radial fracture Impact test to obtain dynamic fracture toughness of rock. The results show that the average dynamic fracture toughness of the rock is 4.57 MPa · m1 / 2 when the ratio of the center hole diameter to the disk diameter r0 / R ∈ (0.10,0.30), and the test value is affected by the change of the center hole diameter The impact is not obvious. The fracture modes of the specimens are different. When the diameter of the hole is small, secondary cracks are initiated during the propagation of the main crack. With the increase of the pore size, the secondary cracks decrease, and the specimens show more obvious macroscopic Pull through the destruction. It is of great importance to test the dynamic fracture toughness of Brazilian circular disk in the center of a round hole crack platform of the promotion center and to grasp the damage characteristics of the rock under dynamic impact.