不同侧压力系数对隧道开挖稳定性影响的数值模拟研究
Numerical Simulation Study on the Influence of Different Lateral Pressure Coefficients on the Excavation Stability of Buried Tunnel

本文以探究不同侧压力系数对隧道开挖围岩稳定性的影响规律为研究目标，采用FLAC3D有限差分软件建立直墙半圆拱隧道模型，通过在隧道关键位置处(隧道顶、底、两侧)布置位移监测点，研究不同测出压力系数条件下，隧道开挖后垂直位移、水平位移的变化规律；在总结隧道开挖后塑性区变化规律的基础上，进一步分析侧压力系数对隧道围岩稳定性的影响规律。研究结果表明：在其余条件保持不变情况下，侧压力系数与围岩塑性区、垂直应力、水平应力皆呈现正相关关系，侧压力系数越大、隧道开挖之后围岩越不稳定，且不稳定区域集中在拱顶、拱底与拱肩处。研究成果可为相似地质条件下隧道开挖过程中的围岩支护提供理论依据。
In this paper, the research goal is to explore the influence law of different lateral pressure coeffi-cients on the stability of surrounding rock in tunnel excavation. The model of a straight wall semi-circle arch tunnel is established by using FLAC3D finite difference software. By arranging dis-placement monitoring points at the key locations of the tunnel (top, bottom, both sides of the tun-nel), the change laws of vertical displacement and horizontal displacement after tunnel excavation under different measured pressure coefficients are studied; On the basis of summarizing the vari-ation law of plastic zone after tunnel excavation, the influence law of lateral pressure coefficient on the stability of tunnel surrounding rock is further analyzed. The research results show that the coefficient of lateral pressure is positively related to the plastic zone, vertical stress and horizontal stress of surrounding rock when other conditions remain unchanged. The larger the coefficient of lateral pressure is, the more unstable the surrounding rock is after tunnel excavation, and the unstable areas are concentrated at the vault, arch bottom and arch shoulder. The research results can provide a theoretical basis for surrounding rock support during tunnel excavation under sim-ilar geological conditions.