地震作用下深埋隧道围岩形变的数值模拟研究

隧道围岩受地震荷载作用影响产生开裂变形,给交通、安全与经济带来极大影响,为提升隧道安全稳定性能,以某市隧道为对象,研究地震作用下深埋隧道围岩形变的数值模拟。综合考虑地震动作用与地震波扩散特性,利用FLAC软件构建三维动力模型;通过边界设置解决地震波反射问题,基于物理力学参数与地震荷载条件,通过相对变形法研究地震条件下深埋隧道围岩变形特性、能量聚集特性与安全性能。研究结果显示:深埋隧道围岩受地震荷载作用影响,形成挤让、椭圆化的变形走向;变形达到最高值时,应变能量密度高于2350 J/m^3的区域集中在隧道Ⅰ洞左侧围岩边墙和中夹岩柱上;各监测点安全系数呈非对称性,隧道右侧下角区域安全系数低于国家相关标准,计算结果与实际测量结果一致。

A Numerical Simulation Study of the Surrounding Rock Deformationof Deep-buried Tunnels Under Earthquake

To improve the safety and stability of tunnels, a numerical simulation study was conducted on the deformation of the surrounding rock of deep-buried tunnels under earthquake. Taking a tunnel in a city as the object, we used FLAC software to build a three-dimensional dynamic model. Based on the physical and mechanical parameters and seismic load conditions, we used the relative displacement method to study the surrounding rock deformation characteristics, energy accumulation characteristics, and safety performance of a deep-buried tunnel under earthquake. The results show that the surrounding rock of the deep-buried tunnel is affected by the earthquake load, which results in the tendency for squeezing and elliptical deformation. When the deformation reaches maximum value, areas with a strain energy density higher than 2 350 J/m³ are concentrated in the tunnel wall on the left side of the surrounding rock and middle rock pillar; The safety factor of each monitoring point is asymmetric, and that of the lower corner area on the right side of the tunnel is lower than the value specified in the relevant national code. The calculated results are in good agreement with the actual measurement results.