构造应力场中层状围岩隧道动力响应数值分析

层状岩层的横观各向同性使得振动波在岩层中沿着不同方向传播时,质点的振动特性有着一定的差异。以我国西南地区某高海拔山区单向公路隧道的全断面爆破掘进为研究背景,利用FLAC 3D软件对构造应力场中均质围岩及倾角不同的层状围岩在隧道爆破开挖过程中的变形、振动速度进行研究。研究结果表明,隧道开挖爆破后,洞周岩体变形不对称式分布,左、右拱腰部位变形最大,均质围岩洞周各部位变形在5种模型中相对较小;爆源距相同时,层状围岩左、右测点的x向振动速度均大于上、下测点的z向振动速度;断层破碎带、层理结构面对于振动波的传播既有消振又有聚振的作用,与断层破碎带和层理结构面的产状、空间关系及振动波相对结构面入射角度有关。

Numerical Analysis of Dynamic Response of Layered Surrounding Rock Tunnel in Tectonic Stress Field

The transverse isotropy of layered rock causes the vibration characteristics of particles certain difference when the vibration wave propagates in different directions.Based on the study background of one-way railway tunnel in a high altitude mountain area in southwest China,the deformation and vibration velocity of homogeneous surrounding rock and layered surrounding rock with different dip angles in the process of tunnel blasting excavation are studied by FLAC3D software.The results show that after blasting,the rock mass around the tunnel is deformed asymmetrically,and the deformation of the left and right sides of the arch is the largest,and the deformation of each part of the homogeneous surrounding rock is relatively small in the five models.The x-direction vibration velocity of the left and right measuring points of the layered surrounding rock is greater than the z-direction vibration velocity of the up and down measuring points when the distance between the blasting sources is the same.The fault fracture zone and the bedding structure have the function of both eliminating vibration and gathering vibration,which are related to the occurrence,spatial relationship and the incidence angle of vibration wave relative to structure surface.