【作者】 王云龙；

【导师】 谭忠盛；

【作者基本信息】 北京交通大学 ， 桥梁与隧道工程， 2013， 博士

【摘要】 隧道施工的安全性与经济性一直以来都是人们最为关注的两大主题。其中安全性取决于隧道围岩与支护结构在施工和运营中的稳定,而经济性则是在保证安全性的前提下减小工程投入,这就需要在隧道的设计与施工中充分认识围岩特点,选择合理的支护参数及施工方法。本文的依托工程贵广铁路板岩隧道为双线铁路隧道群,板岩自身独特的层状结构导致在施工中出现围岩掉块、超挖甚至塌方等工程问题,在这些工程问题中掉块问题影响施工安全性、超挖问题影响施工的经济性、塌方问题则对施工的安全性与经济性均有严重影响。本文以贵广铁路板岩隧道施工安全性与经济性为出发点,详细研究板岩的工程性质从而探究板岩隧道施工中几种工程问题的发生机理,进而对隧道的支护参数及施工方法进行详细优化,主要有如下研究成果：(1)通过对板岩隧道的调查研究,总结了板岩隧道施工中常见问题如大变形问题、掉块塌方问题及超挖问题的影响因素；依据贵广铁路板岩隧道群的调查研究将板岩隧道塌方问题归纳为岩层溃曲型、岩层滑落型与破碎板岩失稳型三种类型,将掉块问题归纳为大块掉落、台阶状掉落及剥离式掉落三种类型,将超挖问题归纳为台阶状超挖、锯齿状超挖及裂隙主导型超挖三种类型,并对各种工程问题的发生条件进行详细统计。(2)在对板岩隧道常见工程问题影响因素统计的基础上对板岩稳定性的影响因素进行归纳,通过岩石室内试验及层间结合物遇水强度等试验研究对板岩稳定性进行亚分级。(3)在理论分析的基础上深入研究岩层溃屈型塌方、岩层滑落型塌方与破碎板岩失稳型塌方的机理,定量或定性分析了板岩隧道几种塌方问题的失稳条件；运用弹性地基梁理论分析了层状岩体的破坏机理,为中厚层板岩的破坏失稳、台阶状掉落及剥离式掉落提供了理论解释。(4)针对隧道施工中的围岩稳定控制问题在施工现场进行大量现场试验,通过各类围岩的围岩压力试验得出适用于板岩隧道的围岩压力计算方法,同时分析了板岩隧道竖向与横向围岩压力的分布规律；通过现场试验与数值分析相结合的手段研究了锚杆在板岩隧道支护中的作用效果,结果显示垂直于板岩层理面施作的锚杆作用最大,其余部位锚杆的作用效果不明显；利用现场试验与收敛约束法相结合的方法研究了钢架的作用效果,着重对比分析型钢钢架与格栅刚架的适用性,结果显示型钢刚架虽然具有较大的安全储备,但格栅刚架的受力特点和经济性较好,并最终得到适用于各级围岩的钢架支护形式及参数。(5)通过理论计算及现场多次试验观察总结了控制板岩隧道超挖的合理爆破方案及辅助施工方法；利用数值分析及理论分析的方法研究了板岩隧道塌方问题的控制方法,针对三种类型的塌方问题提出了相应的开挖工艺,结果表明对于岩层溃屈型塌方及破碎板岩失稳型塌方应以“减小一次开挖跨度、短进尺、管超前”为主要原则,对于岩层滑落型塌方则主要控制掌子面的稳定为主。通过对板岩隧道工程问题的总结分析最终得出了适用于板岩隧道的合理支护参数及施工方法,保证了贵广铁路板岩隧道施工的安全性与经济性。更多还原

【Abstract】 The safety and economy of tunnel construction have always been the two most concerned problems, of which the safety depends on the stability of tunnel surrounding rock and supporting structure when they are under construction and function, while the economy concerns the reduction of construction investment on the premise of safety guaranteed. To achieve those needs a thorough recognition of features of surrounding rock in the process of tunnel design and construction and selection of reasonable supporting parameters and constructive methods. The Guiguang railroad slate tunnels on which this paper relied are double-track railway tunnels, the particular stratified feature of slate may cause many construction issues such as the surrounding rock spalling, overbreak, even collapse, among which the problem of spalling affects safety, the overbreak affects the economy, and the collapse may seriously influence both safety and the economy. This paper takes the safety and economy of Guiguang railroad slate tunnel construction as a starting point, studies in detail the engineering properties of slate so as to probe mechanism of several engineering problems during construction, and thus the support parameters and construction methods can be further optimized detailedly. The research findings are as followes:(1) Through the investigation of the slate tunnels, this paper summarizes the factors causing common problems in the process of construction, such as large deformation、 spallings and tunnel collapses, and overbreaks. According to the investigation and study of Guiguang railroad slate tunnels, the collapses of slate tunnel are categorized into three types of buckling failure of strata、strata slide and instability of broken slate; the spallings are categorized into large-rock spalling, step-shaped spalling and peel-off spalling; the overbreaks are divided into step-shaped over-break, jagged over-break and fracture-leading over-break, and this paper also makes a detailed count on the situations under which kinds of construction problems occur.(2) To sum up the affecting factors of slate stability on the basis of the collection of factors that cause slate tunnel’s common engineering issues. To conduct sub-level classification of slate stability through rock’s laboratory experiment and the experiment of water-weakened degree of cement, and etc.(3) To deeply study the mechanism of collapses of buckling failure of Strata, strata slide and instability of broken slate on the basis of theoretical analysis. Analyze quantitatively or qualitatively the instability conditions of some slate tunnel collapses. Analyze the damaging mechanism of stratified rock by the elastic foundation beam theory; which provides the theoretical explanation for the damage and instability of medium thickness slate, step-shaped spalling, and Peel-off spalling.(4) Plenty of spot experiments have been conducted during tunnels construction concerning issues of surrounding rock stability control, and the calculation method of surrounding rock pressure suitable for slate tunnel is drawn through surrounding rock pressure experiments of kinds of surrounding rocks, and the distribution patterns of horizontal and vertical surrounding rocks pressure are analyzed. The paper studies the effect of anchor in the slate tunnels’ support through a combination of spot experiment and numerical simulation, the result shows that the anchor vertical to the slate bedding plane plays most important role, while the rest of anchor’s effect are not so obvious. The paper studies the role and effect of steel frame through a combination of spot experiments and convergence-confinement method, which puts an emphasis on the comparison of applicability between section steel frame and grid steel frame, the result shows that though section steel frame has larger safety stock, the grid steel frame has better mechanical properties and economic efficiency, and finally obtains the steel frame supporting form and parameters suitable for all levels of slate.(5) This paper summarizes the reasonable blasting schemes and auxiliary construction approaches for controlling slate tunnels’ overbreak through theoretical calculation and several spot experiments, studies the controlling methods of slate tunnel collapses by numerical analysis and theoretical analysis, and proposes specific excavation processing to address the issues of three types of collapses, which proves that it should take " reducing excavation span, short footage、advance reinforcement by small-diameter pipes " as a chief principle regarding to collapse of buckling failure of Strata and Instability of Broken slate; and as to collapse of Strata Slide, the chief principle should be controlling tunnel face.Reasonable supporting parameters and constructing methods for slate tunnels are finally drawn from the summarization and analyses of slate tunnels’ engineering problems, which guarantees the safety and the economy of the Guiguang railroad slate tunnels’ construction.更多还原