【作者】 汪成兵；

【导师】 朱合华； 崔茂玉；

【作者基本信息】 同济大学 ， 结构工程， 2007， 博士

【摘要】 塌方是隧道施工中最常见的灾害现象之一,塌方已成为造成工期延误、生命财产损失和隧道运营的一个重要安全隐患。故此,开展隧道塌方破坏机理方面的研究对设计和施工均具有重要的指导意义。本文结合国家自然科学基金“软弱破碎隧道围岩渐进性破坏分析与松动荷载预测研究”课题,以公路隧道Ⅳ～Ⅵ级围岩为研究目标,采用统计分析、模型试验、数值模拟及理论分析相结合的方法,对自重应力场作用下隧道围岩渐进性破坏机理进行了深入的研究,论文主要工作如下:1.通过文献查阅及现场调研,统计分析了大量公路、铁路隧道和水工隧洞塌方工程实例,对隧道塌方进行了分类,并分析了隧道塌方的主要影响因素;2.在统计分析的基础上,设计了模型试验方案,建立了隧道围岩渐进性破坏机理模型试验方法,对围岩强度、隧道断面、隧道埋深及地表水对隧道渐进性破坏机制的影响进行了一系列的模型试验,总结分析了不同塌方破坏类型的渐进性发展过程、塌方破坏过程中围岩应力及位移变化规律;3.采用离散元软件PFC模拟了隧道围岩渐进性破坏过程,对模型试验方案进行了补充,并对小净距隧道及隧道掌子面塌方破坏机制进行了模拟分析;4.综合统计分析、模型试验及数值模拟的成果,研究了隧道塌方影响因素对隧道塌方发生机制的影响,综合分析了隧道围岩开挖卸荷渐进性破坏机理;5.在模型试验的基础上,提出了基于渐进性破坏的围岩动态压力拱理论,对模型试验过程中压力拱的变化情况进行了分析,较好地解释了试验中隧道周边的应力变化情况,并采用数值模拟的方法进行了比较验证。最后,就存在的问题和进一步的研究方向进行了简要讨论。更多还原

【Abstract】 Tunnel collapse is one of the frequently occurring disasters in tunnel construction, and it leads to great damages, such as the delay in the carrying out the projects, and the loss of life and property, and also poses great latent threat to the safety of the tunnels. Therefore, the research, centering on the failure mechanism of the collapse of tunnels, is of great help and necessity for the design and construction of the tunnels.Basing on the NSFC (National Natural Science Foundation of China) funded project "Research on the Progressive Failure Mechanism of Tunnels Constructed in Soft Rock and the Prediction of Their Loosening Load", this thesis focuses on the progressive failure mechanism of surrounding rocks (grades IV-VI) of road tunnels, by combining statistical analysis, model test and numerical simulation with theoretical analysis.Besides introduction and conclusion, this thesis consists of five chapters.The beginning part is a general literature review and a brief introduction. Chapter One of the thesis examines many instances of the collapse of road tunnels, railway tunnels, hydraulic tunnels by means of extensive reading of files and field researches, classifies these collapses into several types, and analyzes the main influencing factors attributing to the collapse.Basing on these detailed statistic analysis, the succeeding chapter puts forwards the scheme and method of model tests on the progressive failure mechanism of the surrounding rocks of tunnels. Furthermore, by describing a series of model tests, which deal with the influences of the strength of surrounding rock, the cross section and buried depth of tunnels, and the surface water on the failure mechanism of tunnels, this chapter summarizes certain key traits of different types of collapse in terms of the progressive process, the laws of the stress of surrounding rock and their displacement during the collapse.By using DEM software PFC which simulates the whole process of the collapse, the third chapter provides certain supplements to the scheme of model tests, and makes a special analysis of the failure mechanism of the collapse of small-distance tunnels and of the work faces of tunnels.In Chapter Four, a detailed analysis which combines the statistical analysis, model test with numerical simulation leads to the research on the effects of influencing factors on the mechanism of collapse of the tunnels and a comprehensive summary of the progressive failure mechanism of tunnels caused by excavation.The fifth chapter puts forwards the theory concerning the dynamic pressure arch of surrounding rock based on progressive failure, and applies this theory to the analysis of model tests, such as, analyzing the changes of the dynamic pressure arch during the tests, and explaining the changes of the stress of the surroundings of tunnels perfectly. And the numerical simulation is also used to add accuracy and reliability to the theoretical analysis.In the final section comes the conclusion, which summarizes the whole thesis and points out its inadequacies that call for further studies.更多还原