ISSN 1000-3665 CN 11-2202/P

    花岗岩循环爆破振动衰减规律与损伤演化机理试验

    An experiment of attenuation law of vibration and evolution mechanism of damage of granite under cyclic blasting

    • 摘要: 为了研究岩石在循环爆破作用下的动力学响应,本文对黑云母花岗岩试块进行了小型爆破试验,利用加速度传感器和声波测试仪,分别对循环爆破荷载下质点振动衰减规律与累积损伤演化机理进行了探析,并对不同装药量下花岗岩试块的裂纹扩展与断裂形态进行了比较。结果表明:萨道夫斯基公式对室内花岗岩试块的爆破振动衰减规律具有较好的适用性,拟合相关参数都处于0.90以上;花岗岩的爆破损伤随着爆破次数的增加而增加,且损伤值随着距爆心距离(爆心距)的增加而降低,近区损伤值迅速降低,降幅约为1.46/m,而中区和远区损伤值降低相对缓慢,约为0.57/m和0.13/m;花岗岩的破坏程度和装药量有较高的关联度,当药量较低时,岩块致裂所需要的爆破次数就越大;随着药量增加到一定程度,岩块在低爆破次数下就会发生破坏;此外,还发现随着装药量的增加,试块爆后破裂的块数呈现增加趋势,如较低药量时试样破裂成2块,较高药量下破裂成3~4块。

       

      Abstract: To investigate the dynamical response of rock under cyclic blasting, the small-scale blast tests of biotite granite were carried out. By using the acceleration transducer and ultrasonic testing apparatus, the attenuation law of particle vibration and the evolution mechanism of cumulative damage of the granite subjected to cyclic blasting were analyzed, respectively, and the crack propagation and fracture shape of the rock block under different charges were further compared. Results show that the Sadowski’s formula has a good applicability to describe the attenuation law of rock particle vibration in laboratory blasting, and the values of fit goodness are above 0.90. The blast damage of the granite increases with the blast number. Besides, the damage decreases with the increase of the distance from explosive center, and the rock damage of the near area decreases rapidly, with a decreasing amplitude of 1.46/m, while those of the middle area and far area decrease slowly, the amplitudes being 0.57/m and 0.13/m, respectively. The charge amount has a high correlation with the degree of rock damage. When the charge is smaller, the blast number for rock fracturing is higher. When the charge increases to a certain extent, the rock block might be destroyed under a lower blast number. In addition, the number of rock fractures increases as the increase of charge. For example, the sample breaks into 2 pieces when the charge is low, while it breaks into 3 or 4 pieces under a high charge.

       

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