隔振带在浅埋隧道爆破中的作用

研究目的:浅埋隧道上方存在敏感建(构)筑物时,常采用减少一次齐爆炸药量、增设隔振带、干扰降振等综合技术,目前国内对隧道增设隔振带的效果还缺乏定量的评价。本文分析在隧道埋深27 m处采用小导洞先行爆破开挖条件下,隧道上半断面周边设有隔振带时,隧道爆破对地表的振动影响程度。研究结论:弹性边界的特征值分析得到模型第一振型周期为0.203 603 s,粘弹性边界的动力时程分析得到设置隔振带前后的各点振速和加速度,结果表明设置隔振带后竖向振速平均降低39%,竖向加速度平均降低38%。

The Effect of Vibration Isolation Belt on Shallow Tunnel Blasting

Research purposes: The measures and technologies of reducing the explosive charge for simultaneous blasting,building the vibration isolation belt and reducing vibration by interference are often taken and used when there is sensitive building above shallow tunnel,but at present,there is a little quantitative evaluation of the effect of the vibration isolation belt in China.In this paper,the influence of blasting vibration on the surface is analysised when the blasting is conducted for excavation of small pilot tunnel in the 27m buried depth area of the tunnel,and vibration isolation belt is built around the top cross section of the tunnel. Research conclusions:From the analyse of the characteristic values of the elastic boundary,it is seen the fundamental vibration mode period of the model is 0.203 603 s.From analysis of the dynamic time-history of the elastic-plastic boundary,the velocity and acceletation before and after the building the vibration isolation belt are seen.The research result shows that the vertical vibration velocity is reduced by 39 percent in average,and the vertical acceleration is reduced by 38 percent in average when the vibration isolation belt isbuilt.