【作者】 严宗雪；

【导师】 房营光；

【作者基本信息】 华南理工大学 ， 结构工程， 2011， 博士

【摘要】 近年来,随着经济、交通运输的发展,两车道公路已经不能满足交通量增长要求,单洞三车道及以上的大断面公路隧道建设呈现出快速增多的趋势。但国内外针对大断面公路隧道的工程实践不多,施工建设无成熟的经验可参考,可借鉴的设计计算方法更少,无大断面隧道设计、施工的标准和规范可参照,多采用工程类比法进行设计分析。论文针对大断面公路隧道支护形式及参数的合理性尚无统一的认识、围岩稳定性的判别基准尚不确定、大断面隧道的围岩压力及设计计算方法、施工方案的认识尚不够深入等研究现状及难题,结合现场试验、机理分析、数值计算等多种手段,提出了大断面隧道围岩荷载的应力路径设计方法;研究了三车道、四车道和五车道隧道在多种应力路径下对围岩和支护结构的影响;研究了五车道偏压和非偏压隧道在多种工况下的围岩和支护结构的应力路径和空间效应影响;提出了大断面隧道施工的一些安全技术保证措施;从大断面隧道施工的“应力路径效应”和“空间效应”对隧道围岩和支护结构的应力和位移变化特征影响分析等方面开展了一些探索性的研究工作,并把研究成果应用于依托工程的设计和施工。论文的主要研究工作及取得的创新性成果如下:(1)结合依托工程施工过程的围岩变形实测结果,对开挖工序过程的围岩位移变化特征进行了详细的分析研究,得出了大断面隧道分步开挖的松动区扩展范围和规律,并考虑施工应力路径对荷载的影响,提出了较合理的大断面隧道的围岩压力计算公式。(2)基于大断面隧道多个不同工况的应力路径对围岩与支护结构的应力状态和变形性质影响的数值分析结果,深入分析了隧道围岩与支护结构的应力和变形的应力路径效应机制和规律,从应力路径效应新视角来研究相对安全性高、施工风险小的大断面隧道合理的开挖和支护方法。(3)基于大断面隧道空间状况下不同掘进方式和掘进速度的围岩与支护结构的应力和变形的数值计算结果,分析了不同开挖方式的围岩与支护结构的应力和变形分布的空间效应对施工安全状态的影响,探索了大断面隧道的空间效应影响范围和规律,研究了掘进方式和掘进速度对施工安全的影响,为大断面隧道的施工提供有益的参考。(4)以五车道大断面偏压隧道为研究对象,分析了地形对围岩与支护结构的应力和位移的影响,对大断面隧道的偏压角度识别、应力路径效应、位移路线效应及规律等进行了研究,建议了大断面偏压隧道的最适宜的施工方案,为大断面偏压隧道进出洞口施工的安全分析提供借鉴和参考。(5)将本文提出的大断面隧道施工的应力路径荷载设计方法应用于依托工程,并对比现场监测结果,验证了基于应力路径影响的大断面隧道围岩压力计算公式的合理性。更多还原

【Abstract】 In recent years, with the economy and transportation developing, 2 lane road tunnel did not meet increasing demands of traffic, resultly,3 lane road tunnel and above is shown rapid development.But for the large section tunnels, there is a few practice and no mature experience for the struction to be referred ,and there are fewer design calculation methods to be used. At presnt, there are no standard and specifications to be referred for design and construction of large section tunnel, the analogy is the frequent method in the design and analysis.For the present study state and difficulty in the large section tunnel that there is no unified know of suppor form and its charameter, the standard to judge stability of the rock is still uncertain, rock pressure ,design caculation methods and consruction schemes and etc are undeeply studied, combining several ways of site test and mechanism with numerical analysis and etc methods. The paper puts up stress path design method of rock load on the large section tunnel.The paper studies many stress paths’effects on stress and displacement of rock and support for 3 lane,4 lane and 5 lane tunnel, and studies many digging methods’effects on stress and displacement of rock and support for biasing and unbiasing 5 lane tunnel. The paper also proposes some safety gurantee ways of constrution of the large section tunnel and some exploratory jobs are carried out on accout of the effect on the varaity and character of stress and displacement brought by the stress path and space effect, and the study results are successfully used in the project.The main innovations of this study are list as follow.(1) According to the measured results of rock deformation throughout the construction process, this paper analyzes the displacement variation feature during the excavation process, generalizes the extending scale and laws, and based on the influence of the stress path on the load, the calculation formula of rock load of large section tunnel is put up.(2) Based on numerical analysis results of the influence of stress path on stress state and deformation properties of rock and supporting strctures in many different construction conditions of large sections tunnel, the paper analyzes thoroughly the stress path effect mechanism and laws of rock and supporting structure, and provides a new method to study the more safe and lower risk construction scheme of large section tunnel.(3)Based on the numerical results of rock stress and deformation with different excavation methods and speed which is carried out under the space of large section tunnel, this paper analyzes the influence of rock stress and deformation disribution with different excavation methods and the influence of space effect about construction safety state, and explores space effect’s influence scale and rules of large section tunnel, and studies the influence of construction safety of excavation method and speed to provide good refernece to construct the tunnel.(4) This paper takes large section bias tunnel with 5 lane as the research object, analyzes the influence of landform on stress and displacement of rock and the supporting structure, identifies angle bias of large section tunnel, studies the stress path’s effect, displacement path’s effect and laws and etc ,and suggests best construction shcmes to provide reference and consult of safe analysis about the exit and entrance construction of large section bias tunnel.(5) Based on the stress path and space effect on the large section tunnel, the study results are applied in the studied tunnel project and are compared with site monitoring results. It proves reasonable that the calculation formula of rock load of the large section tunnel on account of the stress path and space effect.更多还原