| 切缝药包爆破定向裂纹与张开节理相互作用的实验研究 |
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| 作者姓名： | 丁晨曦 杨仁树 陈程 马鑫民 康一强 赵勇 |
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| 作者单位： | 1.北京科技大学土木与资源工程学院，北京 100083 |
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| 基金项目： | 中国博士后科学基金资助项目（2020M680354）；国家自然科学基金资助项目（51934001，52074301）；中央高校基本科研业务费专项资金资助项目（FRF-TP-20-044A1） |
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| 摘 要： | 为了探究切缝药包爆破定向裂纹与张开节理的相互作用过程，采用动态焦散线方法，结合高速摄影技术，开展了爆破模型实验研究。研究结果表明，张开节理对切缝药包爆破定向裂纹的扩展有阻滞作用，定向裂纹不会穿过张开节理继续扩展，而是在经过与节理相互作用后在节理端部产生两条翼裂纹。当定向裂纹垂直入射时，节理两端的受力状态基本相同，两条翼裂纹的起裂和扩展行为基本一致，两条翼裂纹的分布状态基本对称。张开节理的几何特征对翼裂纹起裂时的动态应力强度因子有显著影响，一定程度上决定了翼裂纹起裂的难易程度。当定向裂纹倾斜入射时，节理两端的受力状态存在差异，靠近定向裂纹入射点的一端能够获得更多的起裂能量，从而优先起裂和扩展，并形成更长的翼裂纹。
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| 关 键 词： | 切缝药包 爆破 张开节理 焦散线 裂纹扩展 |
| 收稿时间： | 2021-02-15 |
Experimental study of the interaction of directional crack and open joint in slit charge blasting |
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| Authors: | DING Chen-xi YANG Ren-shu CHEN Cheng MA Xin-min KANG Yi-qiang ZHAO Yong |
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| Affiliation: | 1.School of Civil and Resource Engineering, University of Science and Technology Beijing, Beijing 100083, China2.Key Laboratory of Ministry of Education for High-Efficient Mining and Safety of Metal Mines, University of Science and Technology Beijing, Beijing 100083, China3.State Key Laboratory for Geomechanics and Deep Underground Engineering, China University of Mining and Technology (Beijing), Beijing 100083, China |
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| Abstract: | To explore the interaction between directional crack and open joint in slit charge blasting, a dynamic caustics method and high-speed photography technology were used to carry out the blasting model experiment. In the model experiment, the polymethyl methacrylate (PMMA) was used as the specimen material, the lead azide (Pb(N3)2) was used as the explosive, and a 3D printed resin material was used as the slit tube. Additionally, varying shapes of the open joint were prefabricated in the specimen. The failure mode of the specimen was described in detail, the initiation and propagation process of the wing crack at two ends of the joint was also analyzed. Research results show that the open joint has a retarding effect on the propagation of the directional crack in slit charge blasting. The directional crack will not continue to propagate through the open joint, but it will produce two wing cracks at the ends of the joint after interacting with the joint. When the directional crack is incident perpendicular to the open joint, the stress state at both the ends of the joint and the initiation and propagation behavior of the two wing cracks are the same, and the distribution state of the two wing cracks is symmetric. The geometric characteristics of the open joint have a significant impact on the dynamic stress intensity factor when the wing crack is initiated. Moreover, it determines the difficulty of the wing crack initiation to some extent. When the directional crack is incident obliquely, the stress state of the two ends of the joint is different. The end, which is close to the incident point of the directional crack, exhibits more crack initiation energy so that the crack is initiated and propagated preferentially and a longer wing crack is formed. |
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