【作者】 曹建安；

【导师】 叶梅新；

【作者基本信息】 中南大学 ， 桥梁与隧道工程， 2011， 博士

【摘要】 无碴轨道因轨道稳定性、刚度均匀性和耐久性好,线路平顺性高,维修工作量显著减少等优点,在国内外高速铁路中的应用日益广泛。但无碴轨道可调量非常有限,对于特大跨度预应力混凝土桥梁,铺轨后,由于混凝土的徐变变形,引起桥梁的上拱或下挠以及轨道的不平顺性。广珠城际轨道交通容桂水道桥是一座(108+2×185+115)m无碴轨道预应力混凝土连续刚构桥,该桥之前国内外还没有在如此大跨度预应力混凝土桥梁上采用无碴轨道。本文以该桥为工程背景,通过徐变变形试验和有限元分析,对高速铁路无碴轨道大跨度预应力混凝土桥梁后期徐变变形和控制问题进行了深入、系统的研究。主要工作和创新性成果如下：1.研究了混凝土结构徐变变形计算理论和计算方法,考察了国内外规范和计算软件对于大跨度预应力混凝土桥梁徐变变形计算的适用性,确定了广珠城际轨道交通容桂水道桥后期徐变变形的计算理论和计算方法,完成了后期徐变变形的分析计算。2.完成了大量的混凝土徐变性能试验,考察了粉煤灰和矿粉等掺量对C60高性能混凝土徐变性能的影响,提出了广珠城际无碴轨道大跨度预应力混凝土桥梁混凝土配合比,并完成了现场混凝土性能试验验证。3.模拟容桂水道桥受力状态,采用现场混凝土原材料和配合比,设计、制作了3根预应力混凝土试验梁,完成了762天的徐变变形试验,研究了预应力混凝土梁徐变变形发展规律、预应力加载龄期、恒加载龄期、环境温度和湿度等因素对预应力混凝土梁后期徐变变形的影响。结果表明,适当延后预应力张拉时间和铺轨时间可有效控制无碴轨道预应力混凝土梁的后期徐变变形。4.对比研究了后期徐变变形各种控制方法的控制效果,结合容桂水道桥的实际施工条件,提出了后期徐变变形联合控制措施并应用于实桥。计算结果表明,该法可行,有效,铺轨20年后,边跨后期变形控制在12.8mmm以内,中跨后期变形控制在21.9mm以内,远小于规范规定的无碴轨道桥梁变形限值。上述部分研究成果已成功应用于广珠城际容桂水道桥的设计、施工,取得了良好的社会、经济效益。更多还原

【Abstract】 Ballastless track is applied increasingly widespread in high-speed railway home and abroad for its stability, uniform rigidity, endurance, high smoothness and remarkably less repairment. However, the adjustability of ballastless track is very small. Therefore, as to large span prestressed concrete bridge, creep deformation of concrete will cause hogging or deflection and unsmoothness of track. The Ronggui Bridge on Guangzhou-Zhuhai Inter-city Rail is a ballastless track prestressed concrete continuous rigid frame bridge with spans layout of (108+2×185+115) m. Before this bridge ballastless track has not been applied in such a large span prestressed concrete bridge home and abroad. Taking this bridge as background, through creep deformation tests and FEM analysis, the problems of late creep deformation and its control on high-speed railway ballastless track large span prestressed concrete bridge were deeply and systematically studied. Main work and creative results were listed below.1. Calculation theory and method of creep deformation of concrete structures were studied. The applicability of standards and calculation software home and abroad on large span prestressed concrete bridges was investigated. Calculation theory and method of post creep deformation of the Ronggui Bridge on Guangzhou-Zhuhai Inter-city Rail were determined and analytical calculation of post creep deformation was finished.2. A number of tests of creep properties of concrete were finished and influences of add contents of fly ash and slag on creep properties of high-performance concrete C60 were investigated. The mix ratio of concrete used on ballastless track large span prestressed concrete bridges was put forward and in-situ tests of performance of concrete were finished.3. Three prestressed concrete test beams were constructed by simulating mechanical behavior of Ronggui Bridge and applying raw material and mix ratio of in-situ concrete and creep deformation tests of 762 days were finished. The developing laws of creep deformation of prestressed concrete beams, influences of prestress age, second term dead load age, environmental temperature and humidity on post creep deformation of prestressed concrete beams were studied. The results show that post creep deformation of ballastless track prestressed concrete beams can be effectively controlled by postpone the time of prestressing and laying track appropriately.4. Controlling effects of various controlling methods of post creep deformation were comparatively studied. Combined with practical construction conditions of Ronggui Bridge, joint controlling measures of post creep deformation were proposed and applied on this bridge. Calculation results show that the method is feasible and effective. The side-span and middle-span post creep deformations are controlled in 12.8mm and 21.9mm respectively. They are much smaller than the limit of ballastless track bridges in standard.Parts of the above-mentioned studying results have been successfully applied in design and construction of Ronggui Bridge. Good social and economic benefits are achieved.更多还原