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偏压浅埋隧道受力特殊,所处工程地质环境复杂,荷载与抗力不明确。隧道车道数的不同使隧道围岩受力、位移产生了变化,在偏压浅埋情况下更加复杂。以广东龙头山隧道工程为背景,在相同偏压浅埋条件下选取单个隧道研究,对二车道、三车道、四车道的公路隧道用FLAC3D软件进行数值模拟对比分析,研究不同车道数隧道的开挖对围岩稳定性的影响。结果表明:隧道围岩竖向与横向位移随车道数的增加而增加;隧道两侧围岩受到的压应力和拱顶、拱底围岩受到的拉应力都是车道数越多受力越大;三种隧道的塑性区都到达了地表,形状大致相似,且车道数越少受影响区域越小;综合应力、位移、塑性区、变形来看,三车道隧道受偏压影响最大,二车道相对最为安全。
Special stress shallow buried tunnel, where the engineering geological environment is complex, load and resistance is not clear. The difference in the number of lanes makes the surrounding rock of the tunnel under stress and displacement, which is more complicated under shallow bias conditions. Taking the Longtoushan Tunnel project in Guangdong Province as a background, a single tunnel study was conducted under the same conditions of shallow buried depth. Numerical simulations of FLAC3D software for two-lane, three-lane and four-lane highway tunnels were conducted. Influence of excavation on the stability of surrounding rock. The results show that the vertical and lateral displacements of the surrounding rock of the tunnel increase with the increase of the number of lanes; the compressive stress on the surrounding rock of the tunnel and the tensile stress on the vault and arch surrounding rock are all the more The plastic zone of the three kinds of tunnels reach the ground surface, the shape is similar, and the less the number of lanes is, the smaller the affected area is. The comprehensive stress, displacement, plastic zone and deformation show that the three- The lane is relatively safest.