下穿隧道爆破荷载激励下边坡振动预测及能量分析

为解决边坡与下穿近接隧道协同爆破施工安全难题，结合某石油储备基地扩建项目，运用量纲推导、现场实验与信号分析相结合的方法，构建考虑高程影响的振动峰值速度公式，研究隧道爆破振动能量沿坡面的衰减机制。结果显示，边坡同台阶边沿处质点振速峰值大于坡脚处，坡面局部存在振动速度高程放大效应；引入相对坡度H/D的爆破振动模型对坡面质点振速预测精度高，可反映边坡角对高程放大效应的影响；振动速度及能量沿坡面均呈现出近区衰减快、远区衰减慢的传播特性，同时隧道爆破振动能量集中分布在0～300 Hz范围的多个子振频带，且高频能量沿坡面衰减更快，能量卓越频带中值以指数形式衰减，能量最终向低频带集中。

Vibration prediction and energy analysis of slope under blasting load in underpass tunnel

In order to solve the safety problem in the construction of slope and underpass adjacent tunnel by cooperative blasting, based on the expansion project of a domestic petroleum reserve base, the formula of peak vibration velocity considering elevation effect was established, and the vibration energy attenuation mechanism of tunnel blasting along the slope surface was systematically studied by using method combining dimension derivation, field test and signal analysis. The results show that the peak value of particle velocity at the edge of the same step is larger than that at the foot of the inner slope, and there is an elevation amplification effect of vibration velocity on the local slope surface. The blasting vibration formula with relative slope H/D has high accuracy in predicting the particle vibration velocity on the slope, and can reflect the influence of slope angle on the elevation amplification effect of vibration velocity. The vibration velocity and energy decay faster in the near region and slower in the far region with the increase of propagation distance. The energy of tunnel blasting vibration is concentrated in several Sub-vibration frequency bands in the range of 0-300 Hz, and the high frequency energy decays faster along slope surface. The median of dominant frequency band decays exponentially, and the energy concentrates in the low frequency band eventually.