隧道掘进中掏槽孔爆破引起的地表振动波形预测

为了研究钻爆法隧道掘进中掏槽孔爆破对地表的影响,建立了隧道工程中掏槽孔爆破引起的地表振动波形的预测方法。首先,从弹性半无限介质中球形药包爆破引起的地表振动波形理论解出发,根据实际介质的地表振动特性构造出一个适用于实际介质且更加简洁的球形药包地表振动波形函数,并用实测数据验证构造函数的正确性;然后,将隧道掘进中掏槽孔的爆破简化为单孔柱状药包的爆破来分析掏槽孔爆破引起的地表振动波形,再利用球形药包叠加法得到简化后的单孔柱状药包爆破引起的地表振动波形函数,从而得出掏槽孔爆破引起的地表振动波形;并讨论了不同围岩等级对隧道掏槽孔引起的地表振动波形的影响;最后以大坪山隧道为背景,利用现场实测数据验证了上述预测方法的正确性。

Prediction of surface vibration waveform caused by cuthole blasting in tunneling

The surface vibration waveform function caused by cuthole blasting in tunneling in actual rock medium is established. Based on the spherical charge, the theoretical solution of surface vibration waveform caused by the spherical charge blasting in elastic semi-infinite medium is derived by using the Hoop point source theory, and a more concise surface vibration waveform function of the spherical charge suitable for actual medium is then, constructed according to the surface vibration characteristics of the actual medium. Secondly, the blasting of cuthole in tunneling is simplified to the blasting of single-hole cylindrical charge. Finally, the vibration waveform function of the spherical charge is superimposed to obtain the surface vibration waveform function caused by the simplified cylindrical charge blasting, thus the surface vibration waveform caused by cuthole blasting is obtained and applied to actual tunnel engineering, and the influences of different surrounding rock grades on the surface vibration waveform caused by tunnel cuthole are discussed by using the vibration velocity waveform function.The surface vibration waveform function obtained in this study provides a scheme for predicting the surface vibration waveform of tunnel excavation blasting, and has certain engineering value.