连拱隧道下穿既有建筑物爆破方案优化动力研究

Dynamic Study on Scheme Optimization of Blasting for Double-arch Tunnel undercrossing Existing Building

隧道下穿既有建筑物爆破振动是城市地下工程中的关键科学问题。以在建五山连拱隧道穿越农业银行工程实践为依托,建立三维动力有限元模型,研究爆破引起的建筑物基础振动速度分布规律、范围及控制技术。掏槽眼爆破只存在单临空面,岩体对炸药约束较强,成为爆破控制关键。建议五山连拱隧道爆破进尺为1 m;中导洞掏槽眼同时爆破;上导洞掏槽眼采用分段两次爆破,降低一次爆破炸药量,建筑物桩基础振动速度才能满足规范要求。研究成果指导五山连拱隧道下穿既有建筑物施工。

Vibration of blasting induced by construction of double-arch tunnel undercrossing exist- ing building is a scientific problem during urban understand engineering. By taking on Wushan double- arch tunnel undercrossing agricultural bank, three dimensional dynamic finite element model was carried out to investigate distribution of vibrant velocity, range and controlled technology. Rock mass has strong restriction on explosive. There is single free-face for cutting blasting. Cutting blasting is deemed as key measure. The blasting footage of Wushan double-arch tunnel is suggested as 1 m. Simultaneous blasting of cutting for middle drift should be adopted, but segmented blasting of cutting should be used for upper drift. Explosive charge for one time blasting is reduced. The vibration of blasting of pile foundations could meet code requirement. The research result can guide construction of Wushan double-arch tunnel undererossing existing building.