【作者】 张敏；

【导师】 黄润秋；

【作者基本信息】 成都理工大学 ， 地质工程， 2009， 博士

【摘要】 随着我国高等级公路的建设发展，山区复杂地质条件下高等级公路隧道洞口段安全、环保和经济性等日益受到人们的重视，公路工程建设越来越注重景观和环境的协调。一般而言，隧道洞口段边坡在自然状态下稳定性较好，传统的隧道施工方法会破坏植被，同时由于对坡体的开挖，会降低坡体下部的支撑能力，影响坡体的稳定性，甚至可能大面积失稳，严重的影响施工安全。大量工程实践表明，隧洞洞口段边坡的变形破坏均与洞口边坡的环境破坏和不合理的进洞方法所致。鉴于此，最好的进洞方式是尽量减少对自然边坡的开挖和自然环境的破坏。本文以黄（塔）桃高速公路沿线隧道为例，通过边坡工程地质条件、岩体结构与坡体结构特征、变形破坏机理、进洞辅助工法、进洞开挖方法、地质与监测反馈分析等研究，遵循系统工程地质分析原理，建立了一套较为完善的山区公路隧道进洞工法技术体系。主要包括：（1）建立了以坡体结构特征分析为基础，隧道围岩和边坡相互作用机理分析为核心，隧道进洞过程的岩土体变形动态监控为支撑的复杂地质条件下大断面隧道“零”进洞工法技术体系，系统阐述了该技术体系的技术原理、施工工序、施工工艺及施工要点。同时，以该体系为基本理念，系统研究了黄（塔）桃高速公路沿线隧道洞口段典型坡体结构的进洞技术。（2）较为详细对坡体结构特征进行了总结分析，并对坡体结构建立中的两个关键因素—结构面体系和工程地质岩组进行了详细的分析研究，针对黄（塔）桃高速公路的工程地质情况，对沿线边坡的坡体结构特征进行了详细的调查分析，并进行了相应的工程地质分类，主要分为层状坡体结构（Ⅰ）、似层状坡体结构（Ⅱ）、软弱夹层坡体结构（Ⅲ）、基座式坡体结构（Ⅳ）、松散破碎体坡体结构（Ⅴ）和块状坡体结构（Ⅵ）；依据上述分类类型，对隧道洞口段边坡的坡体结构特征进行了重点分析研究。（3）在坡体结构特征调查分析的基础上，对隧道洞口段边坡稳定性的主要影响因素进行了系统分析，并以构造地质分析为基础，对隧道洞口段边坡的变形破坏类型进行了基本划分，主要分为坍塌、塌陷、崩塌、滑坡、块体失稳、错落和倾倒等七类。（4）建立了隧道围岩—边坡相互作用概念模型，利用复杂岩土介质的建模技术，采用数值模方法，对隧道进洞过程中围岩和边坡的应力、变形、塑性区的分布及动态变化特征进行了分析研究，结果表明：隧道围岩变形是导致边坡变形的关键因素，同时，洞口仰坡的开挖也为坡体变形提供了更为有利的条件，因此，控制围岩变形和避免仰坡开挖是隧道顺利进洞和洞口段边坡稳定的前提与保证。（5）以围岩应力、变形特征及支护结构的受力特征为基础，以扁平率为技术指标，对大断面隧道的力学效应进行了分析研究。（6）针对浅埋破碎洞口段均压型和偏压型，提出了“先加固边坡，在采用套拱和管棚支护洞口，再进洞”的零进洞工法，重点分析了隧道进洞辅助施工措施的力学效应、隧道围岩及边坡的应力、变形特征，结果表明：①与“传统”进洞工法相比，“零”进洞工法对洞口仰坡向临空面的变形起到了有效的遏制作用；②对于以上两者进洞体系中，套拱与管棚连接处表现为显著的应力集中与应力分析现象，表明此部位易于产生变形破坏，在进行管棚与套拱之间连接处理时，应对套拱钢拱架与管棚钢管间进行有效的焊接；③对于偏压型体系中，耳墙与套拱连接部位至基础底部部位表现为显著的应力集中现象，说明耳墙承受了较大的由套拱传递过来的地形偏压引起的滑移推力，同时，也说明耳墙在抑制由于地形偏压效应导致的边坡滑移变形方面起到了积极的有效作用。（7）针对受结构面控制的隧道洞口段边坡，提出“先治坡、后进洞”的方法，且治坡亦采用和主要结构面近垂直的主动加固措施，以调动岩体本身的抗滑能力，同时根据隧道进洞过程中揭露的地质信息与监测反馈信息对设计与施工进行优化调整。（8）对新型通透肋式拱梁隧道的特点进行了分析，并将“零”进洞工法的理念贯穿于隧洞开挖始终，重点对通透肋式拱梁隧道结构的力学特性、围岩与边坡的应力、变形特征进行了分析。更多还原

【Abstract】 With the development of high-grade expressway construction, people has paid more attention to the tunnel entrance’s security, environment and economic .etc under complicated geological conditions of mountain areas, and taken higher requirements on the road landscape and environment. Stability of tunnel portal slope is better in natural state, while construction will destroy vegetation, and change hydro-geological conditions, the same to reduce support and maybe cause serious problem to effect construction safety. A large number practices shows that the deformation or damage on the tunnel entrance is related to environment damage and unreasonable method of excavating. So, the best way is to minimize the excavation and natural environment damage. This paper, taking Huang (Ta) Tao expressway as example and following the principle of engineering geological analysis, establishes a perfect engineering technology methods system on excavation of tunnel hole ,through slope geological condition, rock mass structure and slope structure features, deformation mechanism, hole-assisted method, hole digging method and feedback research of monitoring. The paper manly includes:The core is to control the slope above tunnel entrance and surrounding rock deformation, make sure its stability and environment protection, establish a technology system of zero cave-entrance about highway tunnel, the system describes the principle, process, techniques and construction of main points. At the same time, based on the concept of system, the paper studies the technology of digging hole on the typical slope at tunnel entrance in Huang (Ta) Tao highway.The paper sums up the slopes characteristics in detail, and analyses the two key factor including joints system and geological groups. Surveying the structure of slopes along line for Huang (Ta) Tao highway geological conditions, and making classification of geology, the slopes mainly divided into layered structure( ), like layered structure( ), soft interlayer structure( ), based slope structure( ), loose body structure( ) and massive structure( ).According to the above mentioned classification, making focus on the slope of tunnel entrance. Based on the survey of slope structure, analyzing the main impact factors on the slope stability of tunnel entrance, and according to structure geology, classifying the slope deformation including mainly collapse, landslide, block failure, bending .etc seven types.Analyzing the interaction mechanism between slope of tunnel entrance and surrounding rock, they are mutually respond to each other, the deformation of surrounding rock is the main factor causing slope failure, and excavation by backstroke will also cause slope deformation, therefore, the main measure is to control the deformation of surrounding rock in tunnel entrance.Based on rock stress, deformation features and force characteristic of support, and index of flat rate technical, analyzing the mechanical effects to large-section tunnel.Based on traditional method of digging hole, using the technology system of zero cave-entrance to the shallow slope with fracture entrance, and analyzing average pressure and bias pressure in terms of relation between slope strike and hole axis, mainly analysis on the mechanical effect of tunnel constriction-assisted, tress of surrounding rock and slope, deformation features, results show that: Compared to traditional method,“zero”system has an containment effect to the deformation toward slope orientation. For the above two types hole, significant stress concentration happens at sets of junction between arch and pipe shed, it shows these areas will be easy to produce damage deformation, so the connections should be welded effectively. For the bias type, the concentration stress happens from the sets of ear wall connecting with arch to the bottom of foundation, it indicates that the ear wall undertakes the push force from arch because of topography, also the ear wall plays a positive role to restrain slope deformation.According to the interaction relation between joint orientation and tunnel axis, analyzing separately on orthogonal and oblique types divided from digging hole system controlled by joints, results show that: This kind slope should use the idea“slope reinforced first, entering cave after”, also can be indicated that analyzing slope structure and deformation mechanism before excavation, and based on the survey previous and geological conditions exposed in site, then, submitting the targeted program and taking optimal designing in accordance with the exposed information and monitoring feedback.Analyzing the characteristics of a new type drafty tunnel with ribbed arch beam, using the concept of the technology system of zero cave-entrance through the whole tunnel construction period, and with a focus to its mechanical features, surrounding rock and slope stress and deformation features.更多还原