倾斜地表条件下隧道开挖面稳定与地表塌陷控制研究

【作者】 严中；

【导师】 阳军生； 张学民；

【作者基本信息】 中南大学 ， 土木工程， 2011， 硕士

【摘要】 在山岭隧道施工中,由于洞口段围岩条件差,常以土质围岩和全风化围岩为主,并伴随着山体的纵向推力和偏压作用,使得隧道洞口段开挖面坍塌冒顶事故常有发生。因而,洞口段施工是隧道施工中的重点难点地段。本文针对隧道洞口段的工程地质特点,在详细的现场调查和文献查阅的基础上,对隧道洞口段开挖面失稳特征进行了数值模拟研究,并针对维持洞口段开挖面稳定而提出相应的超前预加固措施。主要研究内容如下：(1)详细分析了河源洞、狮子垄隧道开挖面坍塌的工程案例,介绍了坍塌的经过,坍塌的形态特征,并分析了坍塌发生的原因,然后通过文献查阅和现场实际调查,总结了部分隧道洞口段开挖面发生坍塌的工程实例,总结得出洞口段隧道开挖面失稳规律；(2)通过FLAC3D有限差分程序,针对不同工况下隧道洞口段开挖面失稳情况进行模拟计算,研究开挖面失稳引起的相应的地表沉降、开挖面位移、塑性区分布、开挖面附近围岩应力重分布等规律,得出隧道洞口段开挖面失稳的形态特征；(3)提出维持开挖面稳定的超前预加固措施,利用数值计算方法评价其预加固效果,对比分析得出维持开挖面稳定的合理的预加固措施。更多还原

【Abstract】 In the construction of mountain tunnels, the portal section has bad surrounding rock conditions, which consists mainly of terrene surrounding rocks and the completely-weathered surrounding rocks with the help of the mountains’longitudinal thrust and bias pressure, leading to accidents of roof falling and the cave-in of the heading face at the tunnel portal section. Therefore, the tunnel portal section is always an important and difficult part in tunnel construction.Focusing on geological and engineering characteristics of the portal section, this article goes on field investigations and document retrievals in details about the tunnel heading face’s features of collapses, and at the same time uses FLAC3D to do numerical simulation and research on its collapse as well as puts forward related the advance strengthening measures. The mainly research contents are as followings:(1) Specifically analyze engineering projects of collapses of He Yuandong and Shi Zilong tunnel heading face, introducing the process and morphological feature of the collapses, analysing the reasons of collapses, summarizing the project cases of working face collapses at the entrance sections of certain tunnels and the collapse rules;(2) Through FLAC3D, focuse on different working conditions and do numerical simulation for the collapse of heading face of tunnel portral, study its related ground settlement, heading face displacement, distribution of plastic zone, stress redistribution and so on, obtain the morphological feature of the working face unstability at the tunnel entrance section;(3) Put forward the advance strengthening measures to ensure the working face stability, evaluate its effects through numerical simulation, draw a conclusion on the reasonable measures to ensure the heading face stability according to a contrast and analysis.更多还原