CRTS Ⅱ型无砟轨道结构体系施工阶段行为分析

【作者】 武鹏宇；

【导师】 卫军；

【作者基本信息】 中南大学 ， 土木工程， 2011， 硕士

【摘要】 CRTSⅡ型板式无砟轨道脱胎于德国博格纵连板式无砟轨道,如今已在我国京津城际、京沪高铁的建设中得到应用。然而中国国情与国外不同,对国外的技术应结合实际情况进行消化吸收,从而创建具有中国自主知识产权的无砟轨道技术。本文从无砟轨道施工建设到投入运营的时间主线入手,重点研究轨道板体系在高速铁路运营前与高速铁路运营后两个时间阶段内特定工况下的应力变形情况。首先,运用ABAQUS有限元软件,在考虑自重、板中配筋、轨道板预留缝构造及板间复杂接触作用等因素的基础上,建立了路基上CRTSⅡ型无砟轨道整体空间模型,并使用该模型与设计结果进行了校准；其次,建立了CRTSⅡ型无砟轨道从施工建设到投入运营的时间主线,对各时间段内轨道板体系所受工况进行了分析,并确定了取值；最后,通过以已建立的时间主线为基准,顺次计算了每个时间段内轨道板、底座板在特定工况下的应力变形情况,得出如下主要结论：1)施工阶段,轨道板安装前,底座板会在温度梯度的周期性作用下发生循环的翘曲变形；钢轨的安装则会减小轨道板的翘曲变形,增大翘曲应力。2)施工完成后,高速铁路投入运营前,整体降温会引起轨道板预留缝开裂；温度梯度会导致轨道板发生上鼓或下凹变形,引起板中脱空或板边离缝现象。3)轨道板预留缝开裂对底座板受力有很大影响,特别是结构处于运营阶段,列车垂向荷载作用于板端时,在整体降温或负温度梯度影响下,底座板板面相应于轨道板开裂处会因过大纵向拉应力而损伤开裂。可见,无砟轨道施工时应采取板面清洁、压紧、保温等措施,保证各部件间的粘结性,并提高底座板的施工质量,加强监控和维护,确保行车安全更多还原

【Abstract】 CRTS II slab ballastless track, based on Bogl longitudinal connected ballastless track, has been used in Beijing-Tianjin Intercity Railway and Beijing-Shanghai Express Railway in our country. However, the situation of the foreign countries is of great discrepancy to our country, and it is important create our home-made ballastless track technology based on the achievements of the predecessors in foreign countries. This paper will analysis the behavior of different component of the ballastless track in every stage from construction to operation.First of all, a finite space mechanical model of CRTSⅡslab ballastless track on the soil formation is established by using finite element software-ABAQUS, and the results of the calculation model have been compared with the results of the design. In this model, the factors of steel ordinances of slab, baste stitch on track slab and contact are considered.Secondly, a time axes from construction to operation of the slab ballastless track is established and the value of the load in every period of time is determined.Finally, the influences of different loads to CRTSⅡslab ballastless track during every period of time are obtained:1) In construction stage, before track slab is installed, cycling warping deformation of base slab will be occurred because of the periodic temperature gradient load. When rail have been installed, the warping deformation of track slab will reduce and the warping stress of track slab will increase.2) When construction is completed, before the high-speed railway is put into operation, the baste stitch on track slab will have cracking problem under the load of lower temperature, the cyclical variation of temperature gradient will cause track slab have warping deformation and gapping problems. 3) The cracking problem of baste stitch on track slab have great influence on base slab especially in stage of operation when vehicle load is located in the edge of track slab, base slab will have cracking problem because of the load of lower temperature or negative temperature gradient.Therefore, heat insulation work and surface clean work should be taken during the construction stage in order to ensure the different component of the ballastless track has good caking property; the quality of base slab should be improved and the maintenance is needed in order to ensure security.更多还原