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首页> 外文期刊>Tunnelling and underground space technology >Frequency comparison of blast-induced vibration per delay for the full-face millisecond delay blasting in underground opening excavation
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Frequency comparison of blast-induced vibration per delay for the full-face millisecond delay blasting in underground opening excavation

机译：地下洞室全断面毫秒延迟爆破爆破振动的频率比较

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Responses and damage to the structures subjected to blast-induced vibration are highly dependent on vibration frequency. Understanding the vibration frequency characteristics and its formation mechanism is essential for the safe and economic design of mining and construction blasts. When millisecond delay blasting is used in excavation, a global frequency value of all of the delays of vibrations fails to present a true picture of the vibration frequency characteristics. In the present study, comparisons of frequency characteristics for the blast-induced vibration per delay were first conducted via an underground opening case excavated by the full-face millisecond delay blasting sequence. The results show that if the blasthole geometry and charge structure are kept the same in each blast delay, the frequencies of single-delay vibration signals will decrease as the dimensions of the equivalent blasting vibration sources increase. However, the cutting blast used for the headmost holes inside is an exception, and its vibration frequency is lower than that of the breaking blast outside. It is the authors' belief that this counter-intuitive phenomenon is caused by the free faces created by the cutting blast for the breaking blast. A small-scale blasting test and the related numerical simulation were subsequently performed to demonstrate this belief. It is found that the vibration frequency from the holes in the free-face blast is higher than that in the confined blast. In terms vibration frequency, therefore, the vibration from the breaking blast is less harmful to structures compared to the cutting blast for a certain velocity, and decreasing the burden of breaking blastholes is beneficial to reduce the vibrational damage of structures. (C) 2015 Elsevier Ltd. All rights reserved.
机译：爆炸引起的振动对结构的响应和损坏在很大程度上取决于振动频率。了解振动频率特性及其形成机理对于采矿和建筑爆破的安全经济设计至关重要。当在挖掘中使用毫秒级延迟喷砂处理时，所有振动延迟的全局频率值都无法真实显示振动频率特性。在本研究中，首先通过全脸毫秒延迟爆破序列开挖的地下洞口案例，对每个延迟的爆炸诱发振动的频率特性进行比较。结果表明，如果在每次爆炸延迟中保持爆破孔的几何形状和装药结构相同，则当等效爆破振动源的尺寸增加时，单延迟振动信号的频率将降低。但是，用于内部最顶孔的切削喷砂是一个例外，其振动频率低于外部的爆破波。作者相信，这种与直觉相反的现象是由切割爆破产生的自由面造成的。随后进行了一次小型爆破试验和相关的数值模拟，以证明这一信念。发现自由面爆破中孔的振动频率比密闭爆破中的振动频率高。因此，就振动频率而言，在一定速度下，与切割冲击波相比，来自爆炸冲击波的振动对结构的危害较小，减少冲击波爆炸孔的负担有利于减少结构的振动损伤。 （C）2015 Elsevier Ltd.保留所有权利。

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