基于FLAC~(3D)的深埋膨胀性黄土隧道初期支护安全稳定性分析

为分析研究深埋膨胀性黄土隧道初期支护后的安全稳定性,依托埋深约为88m的小河沟黄土隧道工程深埋段,借助FLAC~(3D)软件,对设计变更前后的隧道开挖与支护进行了数值模拟,分析了围岩应力和变形、联合支护结构的变形及前方未开挖段的土体位移情况。结果表明,深埋膨胀性黄土隧道施工中,使用管棚外插超前小导管注浆进行超前支护,配合钢拱架和锚网喷联合支护结构,能够有效地提高围岩整体强度和自稳能力,承担围岩荷载,减小土体位移,提高施工安全性。

Analysis on Safety Stability of Deep Tunnel Initial Support in SwellingLoess Based on FLAC3D

In order to analyze and study the safety stability after the initial support of the deep tunnel in swelling loess,based on the deep section of the Xiaohegou loess Tunnel engineering with a depth of about 88 m,a FLAC3D software was applied to the numerical simulation on the tunnel excavation and support before and after the design changed and to analyze the stress and deformation of the surrounding rock,the deformation of the combined support structure and the soil displacement condition of the unexcavated section in front of the tunnel.The results showed that in the construction of the deep tunnel in the swelling loess,a pilot support was conducted with the pilot small duct grouting outside the pipe shield.With the steel arch supports and the bolt/steel mesh/shotcreting combined support,the pilot support could effectively improve the whole strength and self stability of the surrounding rock,could bear the loading of the surrounding rock,could reduce the soil displacement and could improve the safety of the construction.