高速铁路高填方明洞双层衬砌设计方法研究

发布时间：2018-01-31 02:21

本文关键词： 高填方明洞土压力计算双层衬砌受力特性明洞选型施工步序　出处：《西南交通大学》2015年硕士论文　论文类型：学位论文

【摘要】：随着高速铁路路网向西南山区的快速延伸,受山区地形地质影响,隧道数量急剧增多。考虑到隧道洞口周围的环境保护及山区城市自身规划需要,在洞口修建明洞并以弃渣进行回填的方案于近几年开始得到采用,这使得高填方明洞数量逐渐增多。然而目前关于高填方明洞的设计方法尚无规范规定,其洞身土压力的计算方法、结构的选型及施工步序等内容均需进行深入的研究。论文以重庆丰都高填方双层衬砌明洞为研究背景,采用现场试验、理论推导及数值模拟等多种研究方法,对高填方明洞土压力的计算方法、高填方明洞衬砌的结构选型、双层衬砌结构的力学特性及合理的双层衬砌施工步序等内容进行了研究,主要研究成果有：(1)明确了高填方明洞土压力的变化规律,提出了以修正系数为基础的高填方明洞土压力计算方法,并给出了可供设计参考的修正系数建议值。(2)运用沉降差反推法及马斯顿散体极限平衡法得出了适合于各种不同填方高度的明洞土压力计算公式,同时也推导了边墙侧压力公式,并通过现场试验与数值分析对公式的计算结果进行了检验,检验结果表明本文的计算公式具有较好的适用性。(3)基于明洞洞型及明洞基础形式对土压力的影响研究,得出了厚度较高的刚性地基对洞顶垂直土压力的影响十分显著,明洞自身的刚度及明洞边墙的形式均能对垂直土压力产生一定影响的结论。(4)探明了双层衬砌的结构受力特点及内力变化规律,即高填方明洞的内力呈现两段式变化；通过与同尺寸整体式衬砌的受力对比,得到了双层衬砌安全储备量更高且抵抗不利荷载的能力更强的结论。(5)研究了高填方明洞内衬施作时机对结构整体受力及安全性的影响,得到了在施工工期允许的情况下,采取内衬后作的方式能提高结构整体安全储备的结论。论文以多种研究方法互相结合、互相验证的方式,对高填方双层衬砌结构设计中的关键因素进行了研究并取得了一定的成果,为今后高填方明洞的设计提供了一定的借鉴。
[Abstract]:With the rapid extension of the high-speed railway network to the southwest mountain area, the number of tunnels increases sharply due to the influence of the terrain and geology of the mountain area, considering the environmental protection around the tunnel entrance and the planning needs of the mountain city itself. In recent years, the scheme of building an open tunnel at the entrance of the tunnel and backfilling it with waste slag has been adopted, which makes the number of high filling open holes increase gradually. However, there is no standard regulation on the design method of the high fill open tunnel. The calculation method of the earth pressure of the hole, the selection of the structure and the construction sequence need to be deeply studied. The paper takes the double-layer lining tunnel of Fengdu high fill in Chongqing as the research background and adopts the field test. The theoretical derivation and numerical simulation are used to calculate the earth pressure of the high filling tunnel and the structure selection of the lining of the high fill open tunnel. The mechanical characteristics of double-layer lining structure and reasonable construction sequence of double-layer lining are studied. The main research results are: 1) the change law of soil pressure of high filling tunnel is clear. A method for calculating the earth pressure of a high fill open hole based on the correction coefficient is proposed. At the same time, the suggested value of correction coefficient for design is given. 2) by using the method of differential settlement back and the limit equilibrium method of Marston bulk, the calculation formula of earth pressure of open hole suitable for various filling heights is obtained. At the same time, the lateral pressure formula of the side wall is deduced, and the calculation results of the formula are verified by field test and numerical analysis. The test results show that the calculation formula in this paper has good applicability. (3) based on the study of the influence of the open hole type and the foundation form of the open hole on the earth pressure. It is concluded that the rigid foundation with high thickness has a significant effect on the vertical earth pressure of the roof of the tunnel. The conclusion that the stiffness of the tunnel itself and the form of the side wall of the tunnel can have a certain influence on the vertical earth pressure has proved the structural stress characteristics and the law of variation of internal force of the double-layer lining. That is to say, the internal force of the high filling open hole presents a two-stage change; Through the force comparison with the same size integral lining. The conclusion that the safety reserve of double-layer lining is higher and the ability of resisting adverse load is stronger is obtained. The influence of lining time on the whole force and safety of the structure is studied. It is concluded that if the construction period is allowed, the method of lining can improve the overall safety reserve of the structure. The paper combines and verifies each other with various research methods. The key factors in the design of high fill double-layer lining structure are studied and some achievements have been obtained, which will provide some reference for the design of high fill open tunnel in the future.
【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U452

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