软弱围岩地段断层形态对大断面隧道的稳定性影响分析

依托三清高速西山营隧道，采用数值模拟与现场监测的方法，探究断层形态对隧道围岩变形及支护结构稳定性的影响，提出最佳加固方案。结果表明：拱顶沉降最大值随着断层厚度的增加呈"对数"曲线增长趋势，随着断层倾角增大呈"抛物线"曲线分布，当断层倾角达到90°时达到最大；最不利断层形态为倾角+厚度（83°+70 m）；进而建立优化加固对比数值模型，得到管棚注浆加固能够有效控制围岩变形，抑制塑性区发展。结合实测数据发现模拟值与实测值相差较小，验证数值模拟结果的正确性。

Influence of Fault Thickness and Dip Angle on Stability of Large Section Tunnel in Weak Surrounding Rock Section

Relying on Xishanying tunnel of Sanqing expressway, the influence of fault morphology on the deformation of surrounding rock and the stability of supporting structure of the tunnel are explored by using the methods of numerical simulation and field monitoring, and the best reinforcement scheme is put forward. The results show that the maximum value of vault settlement increases in a "logarithmic" curve with the increase of fault thickness. With the increase of fault dip angle, it is distributed in a "parabola" curve, and reaches the maximum when the fault dip angle reaches 90°; and the most unfavorable fault shape is dip angle + thickness (83° +70 m); Then, the numerical model of optimization reinforcement comparison is established, and it is obtained that the pipe shed grouting reinforcement can effectively control the deformation of surrounding rock and inhibit the development of plastic zone. Combined with the measured data, it is found that the difference between the simulated value and the measured value is small, which verifies the correctness of the numerical simulation results.