水平砂泥岩地层隧道爆破振动效应研究

Study on Blasting Vibration of Tunnels in Horizontal Sand and Mudstone Stratum

为了研究水平砂泥岩地层隧道爆破振动效应,以段家坪隧道为例,采用数值模拟,对拱顶、拱肩、拱腰和拱脚的振速和应力以及节理对应力波传播的影响规律进行分析,将数值模拟和现场爆破振动数据进行对比。结果表明:拱顶处的振速和应力最大;随着岩体中水平岩体层数的增加,K值减小,α值增大;水平层状岩体模型中,节理两侧的振速与应力衰减幅度较均质模型中大;由于实际隧道围岩并不是均质的,现场监测振速数据拟合出的振动波衰减指数α偏大。

In order to study the blasting vibration of tunnels in horizontal sand and mudstone stratum,taking Duanjiaping Tunnel as an example,velocity and stress at the various locations of vault,shoulder,waist and foot of arch as well as the influence of joints on the propagation of stress wave were analyzed by numerical simulation.Numerical simulation and field blasting vibration data were compared.Results show that the vibration velocity and stress at the vault top are the largest.With the increase of the number of layers in the rock mass,the K value decreases and theαvalue increases.The attenuation amplitude of vibration velocity and stress on both sides of the joints in the horizontal layered rock mass model is larger than that in the homogeneous model.Due to the inhomogeneous nature of surrounding rock of the actual tunnel,the attenuation index of vibration wave fitted by the in-situ monitoring vibration velocity data is larger.