隧道掘进爆破震动放大效应试验研究

通过渝怀铁路人和场浅埋隧道掘进爆破现场试验,进行隧道特殊位置处质点振动特征研究.以实测振速波形为基础,分析掌子面前后的地表振动速度和隧洞内变断面处的质点振动速度变化规律.对试验研究成果的分析发现,成形隧道对岩体整体结构的改变导致地表振速产生放大效应,使得成洞区地表的振动速度是未开挖区对称位置处的1.310～2.056倍,特别是掏槽爆破的振动放大效应更为明显;在隧道断面由小变大处,同样存在对爆破引起的质点振动速度的放大作用,其放大倍数达1.5～2.1以上.为此,应注意避免隧道掘进爆破的振动放大效应对施工产生的不利影响.

Experimental Study on Magnifying Effects of Vibration Resulting from Driving Blasting in Tunnel

By the field experiment at Ren Hechang tunnel of Yuhuai railway, the characters of vibration velocity resulting from driving blasting have been studied at the special positions of the tunnel. Based on the actual velocity waves, the variation hales of the vibration velocity have been analysed in front of and behind the ground face and at the region with the digging surface changed. There is magnifying effect of vibration velocity in front of and behind the ground face as the rock structure has been changed due to digged tunnel. The vibration velocity behind the ground face is 1. 310-2. 056 times more than that in front of the ground face. There is also magnification effect of vibration velocity at the region of the digging surface changed from small to large and the magnification is 1.5 - 2.1 times. So to the magnifying effect more attention must be paid to avoid the damage of the tunnel.