大型地下输水涵洞复合衬砌结构优化研究

发布时间：2018-03-08 21:18

本文选题：输水隧洞　切入点：浅埋暗挖法　出处：《清华大学》2014年硕士论文　论文类型：学位论文

【摘要】：大型地下输水涵洞普遍应用于水利市政工程,其复合衬砌结构的选择和设计不仅关系着工程的安全,而且对控制工程投资具有重要意义。由于受地质结构和施工工艺的影响,其结构受力十分复杂,目前没有明确计算理论和方法,每个项目使用的构造方法、计算理论、计算方法不尽相同,结果差异较大。其结果不是造成投资浪费就是存在结构安全隐患。本文系统论述了大型地下输水涵洞施工工法选择、结构形式选定等重要设计要点。并以南水北调中线工程北京段西四环暗涵工程浅埋暗挖输水隧洞为工程案例,对双层衬砌结构的结构型式,施工工法,结构设计理论及计算方法,监测资料等进行了研究。提出了大型地下输水涵洞结构设计和优化的思路是:工程类比、结构力学和有限元计算、有限元分析优化、监测数据反演。首先,根据工程的规模和地质条件,采用类比法初步确定初期支护的厚度、强度、配筋等重要结构参数,并拟定施工步序和施工辅助措施。第二步,采用结构力学法手段验算初步选定的结构参数和步序的合理性。同时建立适用于不同地质情况、不同一衬形式的理论计算模型,推导出符合工程实际的理论计算方法,进行不同工况条件下的衬砌内力计算及配筋理论分析。第三步,采用数值模拟方法,建立符合工程实际的二维及三维有限元数值模型,对输水涵洞结构进行数值模拟分析,获得输水涵洞衬砌整体的应力应变规律,对结构力学法计算成果进行分析、复核,为复合衬砌结构优化提供依据。据此,初步得出了工程结构的优化值和优化参数。第四步,进行综合分析比选,调整结构参数。通过模拟计算研究对复合衬砌一衬和二衬进行结构设计优化的可能性;分析了计算结果对计算参数的敏感性;研究了复合衬砌联合受力结构的传力特点;说明了输水隧洞结构防水设计应重点关注的内容。此外,通过对现场施工期及运行期的监测数据结果进行分析,探讨衬砌结构的受力状态以及应力变形机理。进一步印证结构设计的安全性及计算假定的合理性。通过监测值与计算值的对比分析,得出了一二衬受力的分摊比例及结构优化路径。发现二衬受力分摊比例可以由54%降低到34%。各种研究方法结合使用,保证工程结构设计的安全合理,研究提出工程的安全度和优化空间。本文可供水利、地铁、市政工程设计人员借鉴。在理论、方法上具有指导意义。
[Abstract]:Large underground water conveyance culverts are widely used in municipal water conservancy projects. The selection and design of composite lining structures are not only related to the safety of engineering, but also important to the control of project investment. Due to the influence of geological structure and construction technology, the underground water conveyance culverts are widely used in municipal water conservancy projects. At present, there is no definite calculation theory and method. The construction method, calculation theory and calculation method used in each project are different. The results are quite different. The result is either a waste of investment or a hidden danger of structural safety. This paper systematically discusses the selection of construction methods for large underground water conveyance culverts. Some important design points, such as the selection of structure form, etc., and taking the west fourth ring undercut tunnel in Beijing section of South-to-North Water transfer Project as an engineering case, the structure type and construction method of double-layer lining structure are discussed. The structural design theory and calculation method, monitoring data and so on are studied. The ideas of structural design and optimization for large underground water conveyance culverts are as follows: engineering analogy, structural mechanics and finite element calculation, finite element analysis and optimization, etc. First of all, according to the scale and geological conditions of the project, the main structural parameters such as the thickness, strength and reinforcement of the initial support are preliminarily determined by analogy method, and the construction sequence and construction auxiliary measures are drawn up. The structural mechanics method is used to check the rationality of the preliminary selected structural parameters and sequence. At the same time, the theoretical calculation model suitable for different geological conditions and different lining forms is established, and the theoretical calculation method is derived, which accords with the engineering practice. The internal force calculation and reinforcement theory analysis of lining under different working conditions are carried out. In the third step, the 2D and 3D finite element numerical models, which are in accordance with the engineering practice, are established by using numerical simulation method, and the structure of the culvert is numerically simulated and analyzed. The stress-strain law of the whole lining of water conveyance culvert is obtained, and the calculation results of structural mechanics method are analyzed and checked to provide the basis for optimization of composite lining structure. Based on this, the optimized values and parameters of engineering structure are preliminarily obtained. 4th steps are obtained. The possibility of structural design optimization for the first and second linings of composite lining is studied by simulation calculation, and the sensitivity of the calculation results to the calculation parameters is analyzed. This paper studies the force transfer characteristics of composite lining combined force structure, explains the main contents of waterproofing design of water conveyance tunnel structure, and analyzes the monitoring data of site construction and operation period. The stress state and stress deformation mechanism of lining structure are discussed. The safety of structure design and the rationality of calculation assumption are further confirmed. It is found that the distribution ratio of two lining forces can be reduced from 54% to 34. All kinds of research methods are combined to ensure the safety and reasonableness of engineering structure design. This paper can be used for reference by designers of water conservancy, subway and municipal engineering. It is of guiding significance in theory and method.
【学位授予单位】：清华大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TV672

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