穿越高地应力活动断层小净距隧道变形特性及控制技术研究

发布时间：2018-04-29 01:39

本文选题：小净距隧道 + 地应力　；参考：《北京交通大学》2016年硕士论文

【摘要】：作为分离式隧道的补充型式,小净距隧道可以有效解决分离式隧道最小净距要求所带来的占地面积大、开挖土方多、展线不灵活、高边坡等问题。在地形限制、地层改变等情况下,双洞单线分离式隧道变为单洞双线大断面隧道时,过渡段也必然会出现小净距段落,因此对小净距隧道的研究工作日益重要。由于小净距隧道的研究工作尚不全面,尤其是对穿越西南山区活动断裂带的设计理论和应用未达成熟,无法满足实际工程的需要。本文所依托工程成兰铁路柿子园隧道位于龙门山断裂带,其小净距段落穿越两条断层活动带,构造应力显著,在小净距隧道施工时易出现围岩及支护结构的稳定性破坏。通过对现场调研、理论分析、室内试验、地应力测试、数值模拟、现场监测等方法的综合运用,对穿越断层破碎带、局部高地应力突出的小净距隧道变形特性及应力特性进行研究。(1)通过资料收集分析与现场调研,对柿子园隧道隧址区的地层岩性、地质构造有一个较为清晰的认识。利用周边钻孔分析成果和现场地应力测试结果相互比较验证,对隧址区的地应力环境进行评价,同时分析地应力对围岩稳定性的影响；通过岩样的室内试验取得围岩岩块的物理力学参数,运用H-B准则得出较为可靠的隧道围岩力学参数。(2)在取得隧道现场围岩力学参数及了解地层结构特征的情况下,利用大型有限差分软件Flac3D对小净距隧道进行数值模拟施工,取得其在不同条件下施工时对应的的应力特性、变形特征,分析了围岩岩性、隧道净距、水平应力等因素的变化对小净距隧道施工稳定性的影响,之后通过调整设计方案及施工方法进行衬砌结构力学状态的优化研究,得到高地应力环境下穿越断层影响带的小净距隧道合理的稳定性控制技术。(3)通过对实际工程施工过程中的应力、变形等数据进行监测统计,分析了实际工程中围岩应力及位移的变化规律,后行洞施工对邻近先行洞的影响规律,为该隧道小净距段落控制技术研究以及同类型工程提供参考。(4)通过对已有深埋软岩隧道仰拱开裂的一般原因及处治措施进行总结,分析柿子园隧道仰拱开裂原因及开裂机理,针对性的提出开裂段落的整治措施和后续段的施工建议,最终取得良好的效果。
[Abstract]:As a supplementary type of separated tunnel, the small clear distance tunnel can effectively solve the problems of large area of land occupied, more earthwork excavation, inflexible stretch of line and high slope caused by the minimum net distance requirement of separated tunnel. Under the condition of terrain restriction and stratum change, when the double tunnel is changed into a single tunnel with two lines and large section, the transition section will inevitably appear small spacing section, so it is increasingly important to study the small clean distance tunnel. Because the research work of small clear distance tunnel is not comprehensive, especially the design theory and application of active fault zone crossing southwest mountain area is not mature, it can not meet the needs of practical engineering. The Shiziyuan tunnel of Cheng-Lan railway is located in the Longmenshan fault zone. The small spacing section of the tunnel passes through two active fault zones and the tectonic stress is significant. The surrounding rock and the stability of the supporting structure are easily destroyed in the construction of the tunnel with small clear distance. Through the comprehensive application of field investigation, theoretical analysis, laboratory test, in-situ stress test, numerical simulation, field monitoring and other methods, The deformation and stress characteristics of small clear distance tunnel with local high geostress are studied. 1) through data collection and field investigation, there is a clear understanding of stratigraphic lithology and geological structure in the tunnel area of Shiziyuan tunnel. The in-situ stress environment of tunnel site is evaluated by comparing the results of borehole analysis and in-situ stress test, and the influence of in-situ stress on the stability of surrounding rock is analyzed. The physical and mechanical parameters of surrounding rock block are obtained by laboratory test of rock samples, and the reliable mechanical parameters of surrounding rock mass of tunnel are obtained by H-B criterion. The large finite difference software Flac3D is used to simulate the construction of small distance tunnel. The corresponding stress characteristics and deformation characteristics of the tunnel under different conditions are obtained. The lithology of surrounding rock and the net distance of tunnel are analyzed. The influence of the change of horizontal stress and other factors on the construction stability of the tunnel with small clear distance is studied, and the optimization of the mechanical state of the lining structure is carried out by adjusting the design scheme and the construction method. The reasonable stability control technology of small distance tunnel crossing fault influence zone under high ground stress environment is obtained. The monitoring statistics of stress and deformation data in actual engineering construction are carried out. The variation law of surrounding rock stress and displacement in actual engineering is analyzed, and the influence law of rear tunnel construction on adjacent advance tunnel is analyzed. This paper provides a reference for the study of the control technology of the small spacing section of the tunnel and the same type of engineering. By summarizing the general causes and treatment measures of the inverted arch cracking of the existing deep buried soft rock tunnel, the paper analyzes the causes and mechanism of the cracking of the inverted arch of the Shiziyuan tunnel. Finally, good effect is obtained by putting forward the treatment measures of cracking section and construction suggestion of subsequent section.
【学位授予单位】：北京交通大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：U455.4

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