【作者】 周耀；

【导师】 王元丰；

【作者基本信息】 北京交通大学 ， 结构工程， 2008， 博士

【摘要】 地铁车站结构在长期服役过程中,由于环境腐蚀、材料老化、荷载的长期效应、疲劳效应与突变效应等灾害因素的耦合作用,将不可避免地导致结构产生损伤积累、抗力减小,甚至在极端情况下导致结构失效。如果能够对地铁车站结构进行健康监测,将会大大降低事故发生的可能性并减少事故损失。因此地铁车站结构健康监测技术将成为确保结构安全的重要技术。本文以北京地铁10号线地铁车站国贸站为工程背景,对地铁车站结构健康监测理论进行了研究,首次建立了地铁车站结构健康监测系统,并进行2年的结构监测。地铁车站底板大多属于大体积混凝土结构,水泥水化产生大量水化热,容易产生温度裂缝。本文基于等效时间的水化热理论,求解结构温度场,并将该理论应用于地铁车站结构底板温度场的仿真计算中。计算模拟温度场与光纤光栅传感器和振弦传感器测试结果吻合良好。对影响混凝土内部与外部温差的环境温度和板厚进行参数分析,表明温度升高底板中部与上部温差减小,底板中部与下部温差增大;底板厚度增加底板中部与上部温差以及底板中部与下部温差都增大。开展了基于混凝土徐变理论的健康监测分析。基于混凝土双参数徐变模型分析了地铁车站中隔板应变。考虑早龄期徐变计算结果与测试结果总体上更接近,不考虑早龄期徐变计算结果存在较大误差。计算表明早龄期混凝土徐变增大了结构拉应变,对结构早龄期开裂有着重要影响,结构设计和裂缝控制需要考虑早龄期混凝土徐变的影响。基于混凝土徐变B3计算模型和继效流动理论计算模型,分析了北京地铁新型抗渗混凝土结构长期徐变性能,并且基于混凝土B3徐变计算模型对影响混凝土长期徐变的环境湿度、水灰比和骨料水泥比进行了参数分析。由于地下结构的动力响应受周围地基土壤的约束作用显著,其动力响应不如地面结构显著,其研究尚未引起足够重视。本文对地铁车站通过实际监测和理论研究,分析了地铁列车荷载对车站结构动力响应的影响。结果显示车振对地铁车站结构应力影响较小。温度对结构动力行为的影响是结构动力学研究的新方向。本文在理论上推导了在特定边界条件下,温度变化对梁和板结构固有频率影响的方程。基于Kanai-Tajimi模型和三角级数迭加法人工模拟了地震波,在人工模拟地震作用下分析了地铁车站抗震性能。计算表明水平方向地震作用对拱脚和墙脚应力影响较大,拱脚水平方向应力和墙脚水平方向应力分别为初始应力的1.46倍和1.61倍,拱脚竖直方向应力和墙脚竖直方向应力分别为初始应力的1.34倍和1.59倍;竖直方向地震作用对拱顶、拱脚、中隔板跨中、底板跨中、墙脚水平方向应力均有较大影响,对底板跨中水平方向应力影响最大,达到初始应力的3.30倍;对拱脚和墙脚竖直方向应力有较大影响,最大应力分别为初始应力的2.78和2.72倍。同时考虑温度因素的影响,20℃的温度变化对地铁车站结构地震作用应力影响最大达到9.6%,但应力幅值只0.24MPa。首次提出了地铁车站结构健康监测设计方法,并结合北京地铁10号线国贸站建立国贸站健康监测系统。主要监测结构温度、应变、裂缝、徐变等。采集到大量监测数据,并对数据进行了分析。光纤光栅传感器和振弦传感器监测到的同一部位温度和应变数据吻合良好,获得结构受力体系变化时结构应变的变化,以及监测到异常荷载。表明监测系统中布设传感器性能可靠,监测数据可信。开发了基于OpenGL和GIS技术开发的国贸站结构健康监测系统。该系统能采集、分析、管理数据;能实现危险状况预警。更多还原

【Abstract】 Subway station structures which have a long service period are inevitable to suffer from environmental corrosion, long term loading, fatigue effects, material aging and their coupling effects. In the wake of the damage accumulation, performance of the structures will degenerate, and even leading to structure failures under extreme loadings. If health monitoring for subway station is carried out, the possibility of accident will greatly decrease and the losses of accident also reduce. Therefore, the structural health monitoring technology for subway station will become an important technology to ensure structural safety.In this paper taking Guomao Station on No.10 subway line in Beijing as a case, structural health monitoring theories have been studied. The structural health monitoring system for Guomao Station has been installed firstly and the structural monitoring has been carried out for two years.Most of subway station soleplate structures are mass concrete. Cement hydration produces heat, which may provoke important temperature rises in massive structures. Such a high temperature may be a factor for cracking during a cooling phase. A simulation of the evolving temperature field for subway station soleplate is conducted by using the adiabatic temperature rise theory of concrete based on equivalent time. Temperature field simulated agrees very well with experiment data measured by fiber Bragg grating sensors and vibrating wire sensors. Parameters analysis of ambient humidity and thickness of slab which affect the difference of temperature between interior and exterior of concrete are carried out. It is shown that temperature increasesing leads to the difference of temperature between middle and upside of concrete increases, while the difference of temperature between middle and bottom of concrete decreases. Both the difference of temperature between middle and upside and the difference of temperature between middle and bottom of concrete increases.Based on creep theory of concrete, a structural health monitoring analysis is carried out in the paper. Using the double-power law for concrete creep, the strain of septi-slab is calculated. Experiment data measured by fiber Bragg grating sensors agree well with the calculated results, and the calculated results taking into account the earlyage creep are better in agreement with the measured data. Creep has very important effects on earlyage concrete, and the creep of earlyage concrete should be considered in the structural design and crack control. Based on the B3 model and the elastic continuation and plastic flow theory model for concrete creep, the long term creep of new impervious concrete structures is analyzed. The influence of ambient humidity, water-to-cement ratio and aggregate-to-cement ratio are studied with the B3 model.As restrained by earth, dynamic response of underground structures may not significant change from most surface structures. Its study has been ignored for a long time. Through monitoring and theoretical study for subway station, dynamic responses of a subway station are calculated under railway loads. Results show that railway loads have little influence on the stress of subway station structures.Temperature effects on the dynamic performance is a new study direction in structural dynamics. The paper deduces formulae for temperature effects on the natural frequencies of the beam and slab of specific boundary conditions. An artificial earthquake record with the Kanai-Tajimi model and trigonometric series superprosition method is generated. The artificial earthquake record is used to analyze seismic performance of the subway station structure. It is shown that the influences of the stresses of arch springing and basement are significant under horizontal direction earthquake. Under horizontal direction earthquake, the horizontal stresses of arch springing and basement are 1.46 and 1.61 times than the original stresses and their vertical stresses are 1.34 and 1.59 times than the original stresses. It is shown that the influences of the horizontal stress of soleplate and the vertical stresses of arch springing and basement are significant under vertical direction earthquake. Under vertical direction earthquake, the horizontal stresse of soleplate is 3.30 times than the original stress, while vertical stresses of arch springing and basement are 2.78 and 2.72 times than the original stresses. When temperature changes 20℃, the stress of structure changes about 9.6%, while stress amplitude reach 0.24MPa.Design methodology of health monitoring for subway stations is proposed firstly. According to the design methodology, the structural health monitoring system for Guomao Station has been installed to monitor temperature, strains, creep and cracks of the structure, obtaining a great deal of data, the data measured by fiber Bragg grating sensors and vibrating wire sensors of the system agree very well with each other. The change of structure strains at some special cases in the course of construction were obtained. It is demonstrated that the performance of the sensors are reliable and monitoring data are credible.A structural health monitoring system based on OpenGL and GIS which can collect, analyze, manage data and provide an alarm has been developed.更多还原