基于最佳减震原则的新建隧道对既有隧道微差间隔研究

发布时间：2018-06-28 12:24

本文选题：公路隧道 + 钻爆法　；参考：《铁道标准设计》2017年08期

【摘要】：依托新建嘎拉山公路隧道钻爆法施工,利用有限元软件ANSYS/LS-DYNA建立新建隧道采用微差爆破的三维数值模型,模拟3段炸药不同间隔时间延时起爆引起既有隧道的动力响应,得到不同时间间隔微差爆破引起既有隧道二次衬砌质点最大振速点的振速时程曲线。计算结果表明:当新建隧道爆破的总药量分成等间隔时间的三段起爆,使不同段别炸药的作用在时间上和空间上错开,创造新的自由面,能够起到减震和良好的破岩效果。最大振速点发生在既有隧道迎爆侧拱墙上,随着微差间隔变大,既有隧道二次衬砌上振速峰值的发生时间延后。当总装药量相同时,微差爆破与瞬时起爆相比能够有效降低爆破振动对既有隧道的影响,且不同间隔时间下的减震效果有所差异。总药量分三段间隔起爆与瞬时起爆相比,振速峰值减小幅度达到63.1%。当起爆间隔大于20 ms后,每段炸药爆破对既有隧道的影响作用独立开来,振速峰值逐渐收敛于单个药包爆破引起的振速峰值。
[Abstract]:Based on the drilling and blasting method of the newly built Gala Mountain Highway Tunnel, the 3D numerical model of the new tunnel with millisecond blasting is established by using the finite element software ANSYS- LS-DYNA, and the dynamic response of the existing tunnel caused by the delay detonation of three sections of explosives at different intervals is simulated. The time-history curve of the maximum vibration velocity of the existing tunnel secondary lining particle caused by millisecond blasting at different time intervals is obtained. The calculation results show that when the total charge of blasting in the new tunnel is divided into three stages of equal interval, the action of different explosives in different sections is staggered in time and space, and a new free surface is created, which can achieve shock absorption and good rock breaking effect. The maximum vibration velocity occurs on the side arch wall of the existing tunnel, and with the increase of the millisecond interval, the time of peak vibration velocity on the secondary lining of the existing tunnel is delayed. When the total charge is the same, millisecond blasting can effectively reduce the effect of blasting vibration on the existing tunnel compared with instantaneous blasting, and the damping effect is different at different intervals. Compared with instantaneous detonation, the peak value of vibration velocity decreases by 63.1%. When the initiation interval is more than 20 Ms, the effect of explosive blasting on the existing tunnel is independent, and the peak value of vibration velocity converges to the peak value caused by single charge blasting.
【作者单位】：西南交通大学交通隧道工程教育部重点实验室;成都西南交通大学设计研究院有限公司;成昆铁路有限责任公司;
【基金】：中央高校基本科研业务专项资金资助(SWJTU11ZT33) 教育部创新团队发展计划资助(IRT0955)
【分类号】：U455.4

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