【作者】 谭光宗；

【导师】 王梦恕；

【作者基本信息】 北京交通大学 ， 岩土工程， 2014， 博士

【摘要】 海底隧道上方为无限的海水,围岩环境复杂,且地质勘察困难,很难在施工前详细掌握隧道工程地质与水文地质条件,施工中存在较多的不确定性,风险事故一旦发生将带来非常严重的损失,小则延误工期、增加投资,大则可能出现灭顶之灾。如何通过深入研究和系统总结,从理论和技术两个方面建立海底隧道风险评估与控制的科学体系显得尤为重要。本文的研究正是以此为契机,依托大连湾跨海通道工程,综合采用文献与专家调研、理论解析、数值模拟和现场资料调研等多种研究手段,对大断面海底隧道建设的安全风险评估与控制对策进行了系统深入的研究,取得了以下研究成果：(1)系统总结了工程风险的基本概念和特点,提出海底隧道建设风险的定义。根据风险管理理论阐述海底隧道工程施工风险的产生机理和作用过程,对孕险环境、致险因子、风险事故、承险体等概念作出明确界定,指出海底隧道建设期全过程安全风险的特点,提出海底隧道核心风险基本特征、影响因素、控制原则,以及风险分析评价的具体程序和方法,建立海底隧道建设风险分析评价模型和风险接受准则。(2)将海底隧道突水风险后果分为生命损失、社会损失、环境影响损失和经济损失(包括直接经济损失和间接经济损失),将可拓工程方法应用于厦门海底隧道左线F1风化槽施工突水后果严重性分析,有效地解决了突水后果严重性损失难以统一衡量的问题。(3)基于国内外常见的风险辨识方法,根据大连湾海底隧道的相关资料和类似工程资料,结合本工程特点和难点对钻爆法、沉管法、盾构法进行安全风险辨识,采用专家调查法并结合数值计算、相关工程资料调研对钻爆法、沉管法、盾构法进行风险分析、评估,分析其影响因素与潜在后果,给出初步的风险等级评定,对可能的重要风险进行罗列,并且提出了相应的控制措施。(4)依托大连湾海底隧道,对工程可行的两个方案分别对应的两种施工方法下的安全风险进行了综合评估,并提出了相应的控制措施。同时对核心安全风险的概念和特点进行阐述,对三种工法海底隧道的核心风险进行分析,在对相关工程资料广泛调研的基础上,对各风险影响因素进行了等级划分,根据隶属度函数得到各因素的等级评价矩阵。采用模糊数学与可拓工程学理论分别预测风险发生可能性等级和后果严重性等级,得到各方案的核心风险均属不可接受风险,为可行的最低风险限度范围,并提出了三种工法核心风险相应的控制措施。(5)通过对备选方案盾构法、沉管法、钻爆法各项风险系数和综合风险系数的分析,指出大断面海底盾构具有软硬不均地层适应性差、机械设备制作难度高、经验少等特点,技术风险、安全风险、经济风险均比较大；大断面沉管法隧道具有施工场地占用大、水下爆破对海洋环境破坏大,浮运、沉放对海上航运有很大影响等特点,环境风险较大;大断面钻爆法海底隧道具有连续掘进距离较长、作业环境差、不良地质段施工风险大等特点,技术风险、安全风险均比较大。经过对大连湾海底隧道两个线位方案相应的两种施工方案的综合比选,推荐采用沉管法修建。更多还原

【Abstract】 Because of the infinite seawater above, the complicated surrounding rock and the difficulty in geological exploration, it is hardly to obtain the geological and hydrogeology situation of submarine tunnel engineering before the construction, in which there are many uncertainties, once the risk accident occurred, it would bring serious losses, which are from a construction period delay and investment increase to a great disasters. It is important to establish the risk assessment and control scientific system of submarine tunnel in two aspects of theory and technology by further research and systematic summarization. This paper relies on the Dalian Bay cross-sea channel engineering, researches on the security risk assessment and control countermeasure of the large section submarine tunnel construction, the research achievements are summarized as follows.(1) This paper summarizes the basic concept and features of engineering risk systematically and puts forward the definition of the submarine tunnel construction risk. And many conceptions such as the risk surroundings, the risk factors, the risk accidents and the risk bodies are defined explicitly, at the same time, the features of the submarine tunnel security risk during the whole construction period, the basic trait, the influencing factors and the control principles of core risk in submarine tunnel constructions and the specific processes and methods of risk analysis assessment have also been proposed in this paper, based on these achievements, the risk analysis assessment model and the risk acceptance criteria are established.(2) The consequences of water inrush risk in submarine tunnel construction are divided into life loss, society loss, surrounding influence loss and economic loss(which include the direct and the indirect economic loss), the extension engineering method is used in analyzing the water inrush consequence severity in the F1weathered trough construction of the left line of the Xiamen subsea tunnel in this paper, and the problem that the water inrush consequence severity loss cannot be considered unifiedly has been solved effectively.(3)Based on the usual risk identification methods at home and abroad, according to the relevant data and the similar engineering data of the Dalian Bay submarine tunnel, and combining the trait and difficulties of this project, this paper identifies the security risk of drilling and blasting method, pipe sinking method and shield driving method, analyzes and evaluates the risks of drilling and blasting method, pipe sinking method and shield driving method by using expert investigation, numerical calculation and relevant engineering data research, at last, the paper presents the preliminary risk grades assessment, spread out the likely fatal risks and puts forward the corresponding control measures.(4) Relying on the Dalian Bay Subsea Tunnel, a comprehensive assessment of security risks of the two construction methods, respectively corresponding to two project feasible programmes, was carried out, the corresponding control measures were also put forward. At the same time, the concepts and features of core risk security have been elaborated, the core risks of three different engineering methods undersea tunnels have been analysed. The various impact factors of risks are classified on the basis of extensive investigation and research on the relevant engineering data, the rank evaluation matrix of each factor is obtained according to membership function.The likelihood level and the severity level of the consequences of risks are predicted by using the theory of the fuzzy mathematics and the Extension engineering.Then, it can be proved that the core risks of the program are unacceptable risks,but in the feasible minimum risk limits.Core risk control measures corresponding to three engineering methods have been proposed.(5) Through the analysis of each risk coefficient and comprehensive risk factor of the alternatives,shield, pipe sinking method, drilling,it has been pointed out:Large cross-section subsea shield has such characteristics as uneven hardness, poor formation adaptability, high difficulty of the production of machinery and equipment less experience, and technical risk, safety risk, economic risk are relatively large;Large cross-section immersed tube tunnel has such characteristics as large usage of construction site, large destruction of underwater blasting on the the marine environment, great impact on the maritime shipping of floating, sinking, and environmental risk are relatively large;Large cross-section drilling and blasting method tunnel has such characteristics anlonger continuous driving distance, poor operating environment, big construction risk of bad geological section, and technical risk, security risk are relatively large.The Dalian Bay Subsea Tunnel two positions corresponding to the for comprehensive comparison and selection, recommended the use of immersed tube construction.After comprehensive comparison and selection of the two kinds of construction schemes corresponding to the two line position program of Dalian Bay undersea tunnel, the immersed tube construction method is recommended.更多还原