【作者】 房倩；

【导师】 张顶立；

【作者基本信息】 北京交通大学 ， 桥梁与隧道工程， 2010， 博士

【摘要】 摘要：我国铁路隧道建设取得了举世瞩目的成就,进入“十一五”期间,一个以客运专线为重点的铁路网建设已经全面展开,隧道修建数量有了突飞猛进的增长。未来10年我国要修建的铁路隧道,其总长度将超过我国已建成的铁路隧道长度总和。在此期间,隧道建设规模与隧道设计理论不完善之间的矛盾日益突出,以经验设计为主的隧道设计方法面临着巨大的挑战,隧道设计中存在的诸多困惑已经严重制约了隧道建设的科学化、精细化、规范化。针对这一系列问题,论文对隧道结构体系变形控制、围岩结构界面形态、支护围岩作用关系等进行了系统深入研究,取得了以下主要研究成果：(1)针对隧道工程特点,建立起包括“围岩-注浆圈-初期支护-二次衬砌”在内的隧道结构体系理论模型。以变形控制为核心,对隧道结构体系中围岩变形的时空特点以及支护体系中各个子构件的变形特点和力学特性进行系统研究,在此基础上提出复合衬砌结构安全性评价方法。(2)采用理论分析,建立隧道围岩结构界面分区模型。基于弹塑性理论,在大量计算分析的基础上提出隧道围岩结构界面的5种分区模式并给出相应的判断方法；在围岩结构界面分区的基础上,针对Ⅱ区和Ⅲ区进行研究,通过数值分析,针对局部化现象提出剪切滑移是这两种分区模式下的主要破坏形态;通过理论分析,给出楔形滑移体位态的计算方法,并给出三维情况下滑裂面的可能形态。(3)采用数值模拟,分析得到围岩结构界面细观扩展过程。通过PFC模拟隧道开挖后围岩裂隙的细观扩展过程,为了更方便的采用PFC进行分析,通过灰关联分析建立围岩宏观力学参数与PFC细观参数之间的关联序列,进而判断颗粒细观参数改变对宏观力学参数的影响程度和影响规律,并建立细观参数和宏观参数对应关系的神经元网络进而实现对宏观力学参数的标定。(4)采用室内模型试验,得到围岩渐进破坏的特点和规律。主持研发、设计了隧道开挖模拟试验系统,该系统由试验台架、接触监测系统、非接触监测系统三部分组成,分别采用粘性相似材料和砂性相似材料对隧道开挖后围岩的破坏特点进行相似试验研究,提出粘性材料围岩具有先楔形破坏后松动塌落的二次破坏特点,对砂性材料围岩的破坏机理和渐进破坏规律进行了分析。(5)针对我国高速铁路隧道的具体情况,从变形控制的角度出发得到支护、围岩的变形特性。考虑Ⅳ、Ⅴ级围岩典型力学参数组合,给出静水压力和非静水压力下围岩特性曲线,得到喷射混凝土、格栅钢架、型钢钢架的支护特性曲线,采用ANSYS分析得到格栅混凝土和型钢混凝土的变形特性和破坏规律,采用FLAC3D分析得到锚杆控制围岩变形的效果。(6)依托多座高速铁路隧道工程,采用现场监测得到二衬的受力特点。指出二衬最不利受力状态是在其拆模时,而且二衬所受的荷载实际上是初期支护传递过来的围岩形变压力,与规范上采用松散体高度计算得到的松动压力是不同的；根据监测数据分析,不同围岩级别条件下,实测荷载作用下二衬安全系数均能够满足安全性要求,并且均大于规范荷载作用下的安全系数;由于二衬在初支稳定后施作,不同围岩级别条件下,初支、二衬间的接触压力的大小大致相仿。更多还原

【Abstract】 ABSTRACT:Railway tunnel construction has achieved great achievements in our country. During the 11th Five-Year Plan period (2006-2010), railway network construction which focuses on PDL (Passenger Dedicated Lines) is in a comprehensive way, and the number of railway tunnels has been growing rapidly. In the next 10 years, the length of railway tunnel to be built is more than the total length of railway tunnel that are completed. Meanwhile, the contradiction between tunnel construction scale and tunnel construction technology is becoming increasingly conspicuous. The confusion exists in tunnel design has seriously constrained the scientification, precision and standardization in tunnel construction. In response to this series of contradictions, systematic studies are made on tunnel deformation control, surrounding rock failure modes, rock-support interaction in this paper and yield the following key findings:(1) Analysis of the mechanical characteristics of tunnel structure system:The concept of the tunnel structure system is put forward, and the interaction between surrounding rock and tunnel support is deeply studied. According to the principle of tunnel deformation control, the deformation features of each sub components in this system are studied. Based on these analyses, theoretical model of the tunnel structure system which includes "surrounding rock-grouting circle-preliminary lining-secondary lining" and safety evaluation method for tunnel structure system are set up.(2) Theoretical analysis on surrounding rock failure modes:Based on elastic-plastic theory,5 failure zone modes of surrounding rock as well as the definition of each mode are given. It reveals that the V-shaped shearing wedge block is the major failure mode for zoneⅡand III. According to theoretical analysis, the analytical method for shearing wedge block is given and the possible failure modes in three-dimensional state are also proposed.(3) Micro-mechanism analysis using PFC:PFC is adopted to simulate the failure process of tunnel surrounding rock that involves the initiation, growth and accumulation of micro-cracks. So as to use PFC in a better way, gray correlation analysis is introduced to establish the relationship between macro mechanical parameters of rock and micro parameters used in PFC. Neural network is also utilized to achieve the calibration of macro mechanical parameters for surrounding rock.(4) Laboratory study on tunnel excavation:Barite powder, quartz sand and vaseline are selected as the components of similar material based on investigation and research. A large number of laboratory tests are made to study the mechanical properties and strength properties of similar material that affected by similar ratio. The relationship between similar material and geotechnical material is finally established according to similar ratio. Tunnel excavation laboratory simulation system is designed under the instruction of author. The system consists of test platform, contact monitoring system and non-contact monitoring system. Cohesive similar material and sandiness similar material are used to simulate different kinds of surrounding rock, connected with these two materials two kinds of failure modes are achieved. Damage mechanism and progressive failure characteristics of these two failure modes are also elaborated.(5) Study on the interaction between preliminary lining and surrounding rock: According to the specific situation of PDL tunnel in China, ground response curve is studied under different mechanical parameters of surrounding rock and different stress state. Support characteristic curves of shotcrete, grid steel frame and section steel frame are analyzed in a theoretical way. The deformation characteristics and failure regularity of grid steel concrete and section steel concrete are studied using ANSYS software. FLAC3D software is also used to analyze the ability of rockbolt in deformation control of surrounding rock(6) Study on the interaction between preliminary lining and secondary lining:4 typical PDL tunnels are selected to monitor the contact pressure between preliminary lining and secondary lining. Combined with on-site monitoring, time-space regulations on contact force are studied. It reveals that the most unfavorable stress state for secondary lining is in the moment when the tunnel lining trolley removes. The stress acts on secondary lining is actually deformation pressure which is totally different from loose pressure prescribed in China Tunnel Standard. The safety factor of secondary lining under measured load is higher than that under standard pressure and it satisfies safety requirements. The measured contact force is roughly in a same level under different geological conditions, so it is possible to reduce the thickness of secondary lining as well as reinforcement.更多还原