群孔微差爆破的地表振动波形预测及其效应分析
Prediction and effect analysis of surface vibration waveform for group hole delay blasting
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摘要: 针对目前已有的群孔微差爆破地表振动波形预测方法的复杂性、费时性和不易操作性等缺点,建立了一种新的群孔微差爆破地表振速波形预测方法,即振速波形函数预测法,并借此分析了群孔微差爆破的地表振动效应。在球形药包的地表振速波形函数的基础上,通过叠加法得到了单孔柱状药包的振速波形函数;并借鉴了Blair的非线性群孔叠加理论,实现了振速波形函数的非线性叠加,得到了群孔微差爆破的地表振速波形函数;将其运用到实际工程中,通过波形函数预测得到的振速波形与实测振速波形在振速峰值、频谱分布和持续时间上都非常吻合,验证了该波形函数的正确性。并通过振速波形函数探讨了微差时间和炮孔数量对地表振动的影响,结果表明:合理的微差时间可以降低振速峰值,且使振动主频偏离保护对象的自振频率,并给出了合理微差时间的得出方法,而炮孔数量对振速峰值和频谱基本没有影响。群孔微差爆破的地表振速波形函数为实际工程中的波形预测提供了一种较为简便的方法,对实际工程中实现安全爆破具有一定的实用价值。Abstract: In order to solve the shortcomings of the existing surface vibration waveform prediction method for group-hole delay blasting, a new method is proposed, and the surface vibration effects of group-hole delay blasting are analyzed. First, the vibration velocity waveform function for single-hole cylindrical charge is obtained by superposing the vibration velocity waveform of spherical charge. Then, using the Blair's nonlinear group-hole superposition theory for reference, the nonlinear superposition of vibration velocity function for single-hole cylindrical charge is realized, and the surface vibration velocity waveform function for group-hole delay blasting is obtained. The vibration velocity waveform predicted by the waveform function is consistent with the measured one in the peak vibration velocity, spectral distribution and duration, which verifies the correctness of the waveform function. The influences of delay time and number of holes on the surface vibration are discussed by using the waveform function. It is found that a reasonable delay time can reduce the peak vibration velocity and make the basic frequency of the vibration deviate from the natural frequency of the protected object, while the number of holes has few influences on the peak vibration velocity and the frequency spectrum. The surface vibration velocity waveform function provides a simple method for waveform prediction in practical engineering, and it is of certain practical value for engineering.