小净距偏压隧道在特殊素填土施工顺序研究

Study on Construction Sequence of Small Clear Distance Bias Pressure Tunnel in Special Plain Fill

在较特殊素填土中,为能更好地确定在相同的施工方法下,不同的施工顺序对改善隧道围岩变形和衬砌内力的影响,文章重点以重庆曾家岩浅埋暗挖隧道为依托,运用二维数值模拟分析,研究在特殊回填土下,隧道不同施工顺序引起的围岩变形、衬砌内力变化、塑性区分布规律。从数值模拟结果可以看出,不同施工顺序下,围岩变形、衬砌内力、塑性区分布存在一些不同,对于重庆曾家岩偏压隧道,采用先较浅埋一侧开挖方法对总体围岩扰动较小、能较好改善隧道偏压,并使衬砌受力安全稳定。

In order to better determine the influence of different construction sequences on the improvement of tunnel surrounding rock deformation and lining internal force under the same construction method,based on the shallow buried tunnel of Zengjiayan in Chongqing,this paper used two-dimensional numerical simulation analysis to study the surrounding rock deformation,lining internal force changed and plastic zone distribution caused by different construction sequence of the tunnel under special backfill soil.From the numerical simulation results,it can be seen that there were some differences in surrounding rock deformation,lining internal force and plastic area distribution under different construction sequences.For Zengjiayan bias tunnel in Chongqing,the excavation method at the shallower side first had less disturbance to the overall surrounding rock,which can better improve the tunnel bias,and made the lining stress safe and stable.