Influence of in-situ stress redistribution on proportional radii of blasting-induced cracking zones in tunnel excavation
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摘要: 基于爆炸应力波作用下爆生裂隙形成机理的研究,采用莫尔库伦准则及最大拉应力准则,研究了围岩应力重分布对爆炸应力波作用下爆生裂隙区比例半径的影响。研究结果表明,围岩应力重分布对爆生裂隙区比例半径有重要影响,隧洞围岩应力重分布将减小隧洞径向爆生裂隙区比例半径,压剪破坏模式下,爆生裂隙区比例半径可降低20%以上,拉伸破坏模式下可降低10%以上。爆炸应力波作用下,岩体更容易沿结构弱面发生压剪破坏。利用围岩的应力重分布作用,可以降低爆破对保留岩体的损伤作用。Abstract: Based on the study on the forming mechanism of blasting-induced crack under blasting stress wave, by adopting the Mohr-Coulomb criterion and the maximum stress criterion, the influence of in-situ stress redistribution on the proportional radius of the blasting-induced cracking zone (PRBICZ) in deep-buried tunnel excavation was explored. Results indicate that the in-situ stress redistribution has great influence on the PRBICZ, and that the in-situ stress redistribution in the rock mass can decrease the radial PRBICZ. Under compression and shear failure, the PRBICZ can be decreased more than 20%; under tension failure, the PRBICZ can be decreased more than 10%. Compression and shear failure of the rock mass is more likely to occur along the soft structure plane under blasting stress wave. The in-situ stress redistribution can reduce the blasting-induced cracking zone.
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Key words:
- mechanics of explosion /
- crack /
- blasting stress wave /
- rock mass /
- in-situ stress /
- tunnel
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