盾构隧道穿越内陆河浅覆土层厚度的计算分析研究

发布时间：2018-01-21 20:24

本文关键词： 盾构隧道覆土厚度浅覆土壁后注浆　出处：《天津大学》2014年硕士论文　论文类型：学位论文

【摘要】：由于我国经济的不断发展,城市对隧道建设的需要日益显著,隧道建设成为当前研究的重要课题,我国复杂的地理环境不断地对隧道技术的发展提出更高的要求。盾构隧道下穿内陆河时,由于隧道坡度不宜过大一般会导致上覆土厚度较小,此处浅覆土受施工的扰动较大,处理不当可能会引起不必要的工程事故,因此对上层浅覆土的研究是解决此类工程问题的关键。本文依托于江阴市澄江西路二期工程,参考大量相关文献,对盾构隧道穿越内陆河处浅覆土的相关机理进行探讨和研究,并用Abaqus有限元分析软件对盾构推进过程进行模拟,并与实际工程进行比较,提出具有可操作性的上层土加固措施。具体工作如下:首先,探讨隧道上层浅覆土受盾构施工的扰动机理和其破坏机理,在前人研究的基础上对引起土体扰动的四个阶段进行验证,得出软土地层施工中不同阶段对土体扰动程度比例。其次,工程中隧道在浅覆土下发生上浮分为“静态上浮”和“动态上浮”。现有计算浅层上覆土厚度的计算公式只考虑施工后静止状态下覆土的受力状态,未考虑施工时注浆压力对上覆土层的扰动,在实际工程中偏于危险,可能会引起不必要的工程事故。本文在现有最小覆土厚度计算公式基础上增加土层所受注浆压力而得出改进的计算公式,讨论c、?、管片外径R、注浆液重度和注浆压力对改进的计算公式与现有计算公式的影响,并论证其合理性。此外,通过有限元分析软件依据刚度迁移原理,模拟隧道开挖的推进过程,计算出隧道开挖过程中的受力及变形分布,探讨不同覆土厚度下隧道开挖对上层覆土影响程度,比较不同覆土厚度下开挖隧道的受力和变形分布,得出此工程的最小覆土厚度,并与理论计算进行比较。最后,探讨加固浅覆土的施工技术措施,并提出适合本工程的加固上层浅覆土的技术措施,并得到实际工程的验证。
[Abstract]:Due to the continuous development of our country's economy, the need for tunnel construction in cities is becoming more and more obvious. Tunnel construction has become an important subject of current research. The complex geographical environment of our country has constantly put forward higher requirements for the development of tunnel technology. When the shield tunnel passes through the inland river, the overlying soil thickness will be smaller because the tunnel slope should not be too large. The shallow overlying soil is disturbed greatly by the construction here, and improper handling may cause unnecessary engineering accidents. Therefore, the study of shallow overlying soil is the key to solve this kind of engineering problems. This paper relies on the second phase of Chengjiang West Road, Jiangyin City, referring to a large number of relevant documents. This paper discusses and studies the mechanism of shield tunnel crossing shallow soil in inland river, and simulates the shield tunneling process with Abaqus finite element analysis software, and compares it with the actual project. The concrete work is as follows: first of all, the disturbance mechanism and failure mechanism of shallow overlying soil under shield construction are discussed. On the basis of previous studies, the paper verifies the four stages of soil disturbance, and obtains the proportion of disturbance degree in different stages of soft soil layer construction. The tunnel floating under shallow overlying soil is divided into "static floating" and "dynamic floating". The existing formulas for calculating the thickness of shallow overlying soil only consider the stress state of the overlying soil under static state after construction. The disturbance of grouting pressure to the overlying soil layer is not considered in construction, so it is more dangerous in actual engineering. It may cause unnecessary engineering accidents. In this paper, the improved calculation formula is obtained by adding grouting pressure to soil layer on the basis of calculating formula of minimum overlying soil thickness. The influence of segment outer diameter, grouting fluid weight and grouting pressure on the improved calculation formula and the existing calculation formula is discussed, and its rationality is proved. In addition, the principle of stiffness transfer is based on the finite element analysis software. By simulating the advance process of tunnel excavation, the stress and deformation distribution during tunnel excavation are calculated, and the influence degree of tunnel excavation on the upper layer is discussed under different overlying soil thickness. By comparing the stress and deformation distribution of tunnel excavation under different overburden thickness, the minimum overburden thickness of this project is obtained and compared with the theoretical calculation. Finally, the construction technical measures for strengthening shallow overlying soil are discussed. The technical measures suitable for this project to strengthen the upper layer shallow soil are put forward, and verified by the actual project.
【学位授予单位】：天津大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U455.43

【参考文献】