复合式中墙无导洞连拱隧道爆破振动影响研究

Blasting Vibration Response of Compound Middle-Wall Double-Arch Tunnel Without Guide Tunnel

为探究不同爆破方案条件对隧道结构的影响,保证施工安全,以某短隧道为例,采用LS-DYNA显式动力数值模拟方法,分析了不同爆破施工方案条件下后行洞对先行洞的影响规律。结果表明:上台阶不同进尺爆破引起垂直中墙方向的振速最大,内圈及周边爆破段大于掏槽及辅助段,迎爆侧振速明显大于背爆侧;沿隧道轴线方向,对应爆破掌子面前方未开挖处的振速大于后方已开挖处的振速,后方振速衰减速率大于前方;上下台阶进尺爆破药量相差不大的情况下,上台阶爆破引起临近隧道中墙以上测点振速大于下台阶,下台阶对拱脚及仰拱测点影响较大。此研究结果对类似工程具有一定的指导意义和参考价值。

In order to explore the influence of different blasting programme conditions on tunnel structure and ensure the safety of the construction,taking a short tunnel as an example,the influence law of trailing tunnel on leading tunnel under different blasting construction programme is analyzed by LS-DYNA explicit dynamic numerical simulation method.The results show that the blasting with different footages on the upper steps causes the maximum vibration velocity in the direction of the vertical middle wall.The inner ring and surrounding blasting sections are larger than the cut and auxiliary sections,and the vibration velocity on the front blast side is significantly greater than that on the back blast side;along the tunnel axis,it corresponds to the blasting palm.The vibration velocity of the unexcavated area in front of the sub-front is greater than the vibration velocity of the excavated area at the rear,and the decay rate of the vibration velocity at the rear is greater than that in the front;when the amount of blasting charge in the upper and lower steps is not much different,the blasting of the upper steps causes the middle wall of the adjacent tunnel to be above the wall.The vibration velocity of the measuring point is higher than that of the lower step,and the lower step has a greater influence on the arch foot and the invert measuring point.