地铁浅埋隧道爆破开挖振动控制研究

Research on Blasting Vibration Control of Subway Shallow Tunnel Excavation

以青岛地铁工程为背景,研究并提出了控制浅埋隧道爆破开挖振动的措施。文章通过对隧道掘进向不同位置的地表振动矢量合速度检测和数据分析,得到了浅埋隧道开挖爆破不同作用类型炮孔引起的地表振动特性及其衰减规律,并以此提出了爆破施工减振措施。试验与分析结果表明:开挖掌子面上不同的炮孔爆破类型其衰减规律有所不同,随着爆破起爆段别的增加,衰减公式中的K值逐渐递减;α由地质条件决定,基本保持不变;根据K、α值的大小和变化规律来调整掏槽方案、改善起爆顺序、减轻爆破夹制作用,大幅度降低了爆破振动;青岛地铁隧道采取全断面开挖时,其衰减参数K值随着段数的增从68逐渐减小到26,α值在1.4～1.6之间。

Taking the project of Qingdao subway tunnel project as the background, this paper studies and propo- ses measures on how to control vibration which appear in shallow tunnel blasting. Through surface vibration vector re- sultant velocity detection and data analysis of different locations after excavation into the tunnel, the paper got vibra- tion characteristics of the surface and attenuation law which induced by different types of hole when excavated and blasted shallow tunnel, and thus proposed blasting damping measures. Experimental and analytical results show： the different blasting types of excavating face decide its attenuation law, with the number of blasting initiation section in- creasing, K value of the attenuation formula decreases gradually ; ct, which is determined by the geological conditions remains unchanged; according to the size and variation law of K, ct values are used to adjust cutting programs, im- prove the initiation blasting order, reduce the role of bursting folder, at last blasting vibration reduced obviously. Qingdao subway tunnel had the whole section excavation, as the number of segments increased, the value of attenua- tion parameters K decreased from 68 to 26, α value was between 1.4 and 1.6.