【作者】 郭建刚；

【导师】 彭芳乐；

【作者基本信息】 同济大学 ， 隧道及地下建筑工程， 2008， 硕士

【摘要】 本研究基于气压沉箱的施工特点,提出了一套定量化评价气压沉箱施工对周围土体影响的数值模拟方法以及气压沉箱施工控制技术。本研究的创新性成果主要体现在以下三个方面:（1）基于气压沉箱的特殊施工工艺,提出了一种能够追踪气压沉箱下沉施工全过程的非线性有限元动态模拟方法与技术;（2）基于系列性的数值模拟和工况分析,定量化地分析了气压沉箱下沉时影响地层变形的主要参数及影响效果;（3）基于数值理论分析结果和特殊的施工工艺,提出了一套完整的气压沉箱施工控制技术和周围环境保护措施。本论文的主要研究内容由如下八部分组成。在论文的第1章中,简要介绍了课题来源、研究背景、研究意义与目的、研究内容、研究计划以及主要创新之处。在论文的第2章中,系统地总结了国内外气压沉箱工法的应用现状及发展动态,分析了一般基坑工程开挖对周围环境影响的研究方法及成果,在此基础上结合国内普遍应用的沉井研究资料,详细论述了国内外学者在气压沉箱施工对周边环境影响方面的研究成果。另外,还对非线性有限元分析方法在地下工程中的应用作了简要的阐述。在论文的第3章中,首先分析了自动化气压沉箱下沉施工的工艺流程以及沉箱下沉施工对地层变形影响的主要因素。然后,基于沉箱分节下沉全过程的动态受力特点以及物理力学模型,创新性地提出了一种能够追踪气压沉箱下沉施工全过程的非线性有限元动态模拟方法和技术。在论文的第4章中,提出了不同于其它施工方法的沉箱实时监测技术与方法,并分析了国内首个采用自动化气压沉箱方法施工完成的隧道风井的监测方案及数据,包括地表沉降、水平位移以及地下水位变化等。在论文的第5章中,利用上述提出的气压沉箱下沉施工全过程的非线性有限元动态模拟技术,根据实际的施工状况和条件,针对国内首个采用自动化气压沉箱方法的隧道风井（地铁7号线耀华路隧道风井工程）,动态模拟了沉箱下沉施工的整个过程,分析了沉箱下沉各阶段对周边地层变形的影响。基于现场实测数据,比较分析了下沉各阶段引起的地表沉降、土体水平位移以及工作室内的土体隆起等,验证了本文所提出的气压沉箱动态有限元模拟方法的合理性。在论文的第6章中,利用上述提出的气压沉箱下沉施工全过程的非线性有限元动态模拟方法,定量化分析了土体弹性模量E、粘聚力C、内摩擦角φ、卸载再加载模量E_ur等土性参数,工作室内气压的大小,沉箱与土体间侧摩阻力的大小以及设置临时挡土隔墙对气压沉箱施工的影响,系统性地分析了各种因素对气压沉箱施工以及周围土体的影响效果。在论文的第7章中,基于以上定量化数值分析结果以及各种因素的影响效果,提出沉箱下沉施工的主要控制技术与保护措施,如沉箱箱体制作控制、下沉姿态控制、工作室内气压管理、沉箱施工设备管理、高气压作业管理、下沉实时监测、沉箱壁外注浆、刃脚超挖控制、设置临时挡土隔墙、局部地基加固等等。在论文的第8章中,对本文的研究工作与主要结论作了总结,并提出须进一步研究的课题。更多还原

【Abstract】 Based on the construction characteristics of pneumatic caisson, a type of numerical simulation method to evaluate the influence of surrounding soil deformation and the corresponding control technique are presented in this paper. The innovation mainly includes the following three aspects: (Da type of nonlinear finite element dynamic simulation method and technique to track the entire process of pneumatic caisson sinkage is presented based on the special construct technics of pneumatic caisson. （2） the main parameters to impact the strata deformation and the influence in the sinkage of pneumatic caisson are analyzed quantitatively based on a series of numerical simulations and working-state analysis. （3） a suit of whole construction control technique of pneumatic caisson sinking and surrounding environmental protection measures are presented based on the results of numerical analysis and the special construct technics.This thesis consists of the following eight parts:In chapter 1, the project source and background, research meaning and objective, main content, research program and main innovation are generally introduced.In chapter 2, the present application and development situation of pneumatic caisson method are systematically summarized and the research measures and results of general pit engineering are analyzed. On previous basis, the research results on the surrounding environment effect due to pneumatic caisson construction are discussed in detail incorporating domestic open caisson research data. In addition, non-linear finite element analysis method applied in underground engineering is briefly mentioned.In chapter 3, the process flow of automated pneumatic caisson sinkage is introduced briefly and the main factors which induce strata deformation are presented. Then, based on the dynamic mechanical characteristics and the physical mechanical model of entire process of caisson sub-section sinkage, a type of nonlinear finite element dynamic simulation method and technique to track the entire process of pneumatic caisson sinkage is creatively proposed.In chapter 4, unlike other construction method the pneumatic caisson sinkage real-time monitoring technology and method are presented. Moreover, the measurement project and data are analyzed, including the ground surface settlement, the horizontal displacement of surrounding soil and the heave of soil in the working chamber of the first tunnel air shaft constructed by automated pneumatic caisson method in China.In chapter 5, by the proposed nonlinear finite element dynamic simulation method, the entire process of pneumatic caisson sinkage is simulated and the influence of surrounding soil doformation is analyzed based on the actual construction status incorporating the first tunnel air shaft constructed by automated pneumatic caisson method in China. The ground surface settlement, the horizontal displacement of surrounding soil and the heave of soil in the working chamber are simulated and compaired with the measure data. It is validated that the presented FEM analysis is valid and accurate for the construction of pneumatic caisson.In chapter 6, by the proposed nonlinear finite element dynamic simulation method, the sensitivity of parameters for the influence to adjacent environment are analyzed, including the soil physical parameters: elastic modulus E, cohesion C, angle of internal frictionφ, unloading-reloading modulus E_ur, and the pressure of compressed air in the working chamber, the side friction between the caisson and soil, the temporary retaining wall.In chapter 7, according to the results of soil deformation by numerical analysis and the effect to soil deformation of main factors, the corresponding control techniques and protective measures are proposed, which include the caisson construction technique, the sinkage state control, the air management in the working chamber, the management of construction equipment, the sinkage real-time monitoring, the spout technique outside caisson, the overbreak control under the cutting curb, the setting of temporary retaining wall,local foundation reinforcement and so on.In chapter 8, the summary of conclusions from this thesis with associated objectives for future studies is presented.更多还原