小净距交叉隧道爆破振动响应研究

新建隧道从既有公路隧道上方穿过,在空间上形成交叉隧道。上下隧道最小净距为8.1 m,为评价新建隧道爆破施工对既有公路隧道结构的影响,进行了数值模拟研究。结果表明:当新建隧道在距离隧道交叉点10 m以外位置以全断面法爆破施工时,下方既有公路隧道仅受到较小的影响;当其在距离交叉点10 m以内位置以全断面法爆破施工时,既有公路隧道二次衬砌振动速度超标,而采用台阶法爆破施工时,新建隧道可安全通过。

Study on influence of blasting vibration on cross tunnels with small clearance

A new tunnel was built to cross over the existing tunnel. The smallest clearance was 8.1 m between the upper and lower tunnels. The effect of blasting that the newly-built tunnel exerted on the existing tunnel structure was evaluated by numerical simulation method. It was indicated that when the rock was blasted with the full face method at a distance of more than 10 m to the cross point, the impact acting on the existing tunnel was relatively small. On the other hand, when the distance was less than 10 m, the vibration speed of the second lining of the existing tunnel exceeded the standard. While the rock was blasted with stepped method, the new tunnel could cross over the existing tunnel safely.