小净距公路隧道爆破震动观测与分析

基于小净距的南方某公路隧道二期工程爆破震动安全监测,通过质点振动速度峰值与主振频率分析,展开了基于小净距公路隧道的爆破震动观测与研究。首先介绍了测线与测点布置原则,并阐述了爆破震动观测及其结果,得出了相应的质点振动速度峰值衰减经验公式及v-ρ关系曲线。结果表明,半断面、下上台阶和全断面爆破等三种不同隧道施工开挖方式所得出的不同的观测结果,质点振动速度峰值最大值通常出现在同一断面的墙中与顶板位置、径向方向和爆心距最小位置发生处,对应主频分布在15~75Hz,主要集中在22~50Hz。结论指出,质点振动速度峰值与对应主振频率与爆破方式以及爆心距密切相关,爆破规模与爆心距对爆破地震效应影响程度很大,隧道开挖中的全断面爆破有利于减小和控制爆破震动。

BLASTING VIBRATION ANALYSIS OF LITTLE-SPACE ROAD TUNNEL

The monitoring analyzation of blasting vibration was regarding an excavation of a new tunnel under a road close to an old one in little-space involved in the 2nd term engineering of road tunnel excavation and was conducted through analyzing the 1919V of blasting vibration and its main frequency. The present paper intro- duced the principles of how to determine the monitoring points and lines together with observation information and results. A attenuation formula of 19PV of blasting vibration and v - p correlation curve were obtained. The curve showed that the maximum peak values of blasting vibration velocity appeared frequently at the point where the apex of arch in same section, the radial direction and the blasting center were in the minimum distance in between, with the main frequency falling into 15- 75Hz, dominantly into 22- 50Hz. The outcome indicated that, the peak value of 19PV and its corresponding main vibration frequency were closely correlated with the blasting method and blasting center distance, and tnat, blasting ability and blasting center distance had great influence on blasting seismic effects. And as a result, full-face blasting was the best blasting method in terms of controlling the blasting seismic effects.