爆破动力作用下小净距隧道围岩振动效应分析

以渝长高速公路武隆小净距隧道掘进爆破为背景,应用FLAC3D数值模拟法进行隧道掘进爆破条件下的前洞围岩振动效应分析.通过计算结果与试验数据的对比分析,证明了应用此计算方法进行振动强度分析的可行性.进一步分析表明,全断面不同循环进尺爆破方案引起振动速度的分布规律基本相同;在爆破掌子面前,前洞迎爆侧边墙上的最大振动速度沿隧道轴线方向随水平距离增大有明显的放大现象,最大振动速度发生在爆破掌子面前面10 m左右前洞断面迎爆侧的边墙上;在爆区附近,前洞迎爆侧围岩上的振动速度是背爆侧的6-10倍.

Analysis of Vibration Effects on Surrounding Rock for Small Clear Distance Tunnel under the Dynamic Action of Blasting

Taking the project of Wulong small clear distance tunnel driving blasting in Yu-chang high speed highway as the background,used FLAC^3D numerical simulation to analyze the vibration effects on surrounding rock in the situation of tunnel driving blasting. By comparing the calculation results with the field monitoring results to testify that this calculation method is feasible to analyze vibration strength. Further analysis show that the distribution ride of vibration velocity caused by different footage full-face blast is approximately the same. Before the blasting tunnel face, as the horizontal distance becomes longer, the maximum vibration velocity on front tunnel abutment wall along tunnel axial line has obvious magnification,where the maximum vibration velocity occurs at 10 m before the blasting tunnel face;the vibration velocity of frunt tunnel surrounding rock facing to blasting is as big as 6-10 times of that on the back of blasting.