浅埋小覆土管线地下穿越对机场道面结构安全影响研究

Shallow Buried pipeline consist the basic infrastructure of airport operation system, while installation of pipelines beneath an operating runway is often needed in airport rebuild and expansion by using trenchless technology. Since the burial depth and span-to-cover ratio of pipeline is small, differential settlement can be caused by the disturbance of foundation soil during pipe jacking, which is a serious safety hazard to pavement structure. Current researches merely focus on the influence of shield tunneling under airport runway, while the foundation soil deformation and pavement stress distribution can be quite different since the cover depth is much larger than that of pipelines. This projects aims at establishing a continuous pavement model build on modified Winkler foundation to study the impact of uneven settlement of foundation soil on the pavement structure. Numerical simulation with accurate modeling and large scale pipe-soil-pavement model test are also adopted in this research, which helps to obtain an quantitative expression of foundation supporting condition and assessment method of pavement voids. In this way, the safety performance of pavement structure on the top of pipe tunneling is studied comprehensively. Research results will supply essential analyzing method and theory for airport underground passing through design.

埋地管线是保障机场运行的重要基础设施，在机场改扩建中普遍存在穿越既有跑道和机坪等施工需要。由于管道埋深浅且覆跨比小，穿越施工容易扰动地基引发不均匀沉陷，形成道面脱空安全隐患。现有研究主要围绕大埋深地铁盾构穿越问题进行，与道面结构层距离较大，地层变形规律和道面受力影响明显不同。对此，本项目拟构建穿越管道上部连续道面板块文克勒地基分析模型，结合精细化建模数值模拟和大比例模型箱试验，通过数据回归分析和理论推导，获得量化的地基支撑条件与道面脱空评价方法，开展穿越管道上方道面结构安全问题研究。为机场穿越工程设计提供理论依据和分析方法。

本课题主要研究不停航条件下飞行区地下浅埋管线穿越施工对跑道地基扰动机理与影响。从以下4个方面开展研究工作：1）从土拱效应原理出发揭示穿越施工引起地层变形特征以及对道面板结构受力状态的影响；2）完成土体沉陷位移条件下道面板（弹性地基梁）变形与弯矩理论解推导，据此编制基于Matlab的道面地下穿越变形分析程序；3）设计并实施大比例道面下部顶管穿越模型试验，采用先进的FBG光纤光栅传感器及BOTDA分布式光纤传感技术测量开挖面上方地基及道面结构变形与内力分布，积累了丰富的试验数据；4）应用ABAQUS有限元软件对机场道面地下顶管穿越施工进行多工况仿真及参数敏感性分析。综合研究结果表明：浅埋管线穿越施工对道面结构安全影响不容忽视，具体反应为道面板支撑力的不均匀变化和板底弯拉应变的增大；分布式光纤应变测量技术可有效监测覆盖层土体变形，土体扰动区范围与开挖面夹角特征符合扰动区划分理论。综合试验数据和仿真结果规律，为道面板理论模型提供了荷载和边界条件，获得了基于汇源法原理的数值解。.截至项目结题时，已发表研究论文3篇（EI检索1篇，核心期刊2篇），获批实用新型专利2项。通过本课题研究工作的开展，探讨了由穿越开挖引起的不协调地基支撑道面变形特征与应力发展规律，理论模型及研究结论可指导工程设计实践，有利于保障道面结构安全与使用性能。