隧道爆破开挖产生地表震动效应的数值模拟

Numerical simulation of ground vibration effect caused by tunnel blasting excavation

为了研究隧道在爆破开挖过程中产生的爆炸冲击波对地表的影响,依托辽宁省丹东市郊附近的爱民山隧道,利用ANSYS有限元软件建立三维模型,经过动力计算得到地表一些特殊点的震速波形图,采用数值模拟方法分析了隧道爆破开挖产生的地表震动效应.结果表明:隧道上方地表的最大震速为32.3 mm/s,小于规定数值,所以地面建筑物是安全的;由于纵波在固体介质中的传播速度快于横波的传播速度,X方向的震速峰值较Y方向出现滞后性,滞后约100 ms;由于空洞效应的存在,导致处于隧道已开挖区的地表震动速度大于未开挖区的地表震动速度,在距离爆源15~30 m处空洞放大效应最为明显.

In order to study the effect of explosive shock wave on ground surface in the process of blasting excavation of tunnels,a three-dimensional model based on Aiminshan tunnel near Dandong city of Liaoning province was built by software ANSYS,and the velocity waveforms of some special points on the ground surface were obtained by dynamic calculation.The ground vibration effect caused by tunnel blasting excavation was analyzed by the numerical simulation method.The results show that the maximum vibration velocity of ground surface above the tunnel is 32.3 mm/s,which is small than the prescribed value,so the ground buildings are safe.Because the propagation speed of P-wave in solid medium is faster than that of S-wave,the peak value of vibration velocity in X-direction lags behind that in Y-direction for about 100 ms.Because of cavity effect,the ground vibration velocity in the excavated area of the tunnel is greater than that in the untapped area,and the cavity amplification effect is most obvious at the distance of 15 m to 30 m from the blasting point.