Study on the propagation rules of double cracks with collinear unequal length under blasting
Received:April 10, 2018  Revised:April 25, 2018
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KeyWord:rock mechanics; double cracks; blasting; initiation angle; extended length
           
AuthorInstitution
韩雪靖 福州大学爆炸力学研究所;福州大学紫金矿业学院
楼晓明 福州大学爆炸技术研究所;福州大学紫金矿业学院
王宝 福州大学爆炸技术研究所;福州大学紫金矿业学院
黄慎 福州大学爆炸技术研究所;福州大学紫金矿业学院
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Abstract:
      In order to study the failure law of fractured rock under blasting stress wave, based on classical Kachanov’s method, the static stress intensity factor at the tip of collinear unequal length crack is derived, and the relationship between the coupling stress intensity factor and the coefficient under dynamic load is obtained with the principle of fracture mechanics. And the theory is verified with different incident angle of stress wave, different crack length and different crack spacing through the model test. The experimental results show that the incidence angle of stress wave, the length of collinear crack and the crack spacing are the important factors that affect the crack propagation. The crack initiation angle varies with the incident angle of the stress wave. The trend of the coefficient is the same as the crack expansion length. The greater the length of the secondary crack and the smaller the crack spacing, the longer the length of the crack tip expands. When the length of the crack is greater than 1.2 times the crack length, it no longer affects the crack tip expansion.
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