高原铁路桥墩大体积混凝土温度场及温度应力分析
发布时间：2019-05-09 03:25
【摘要】：在我国的西北高原地区,铁路不断涌现。这些铁路在建造的时候采用了不少大体积的桥墩和基础。而在大体积混凝土中,温度场的分布和温度应力的分布都是特别复杂的。而在我国的西北高原地区,白天和夜间的温度之差非常大,气候干旱,相对来说气候比较特殊。因此大体积混凝土若是在这样比较特殊的环境中施工,则其温度场的分布和温度应力的分布相对来说就会更加复杂,大体积混凝土就更容易有裂缝产生,从而会导致大体积混凝土结构的正常使用和耐久性受到影响。本文在西北高原地区某双线铁路桥墩施工、养护过程和在现场温度采集的基础上,结合当地同时期的气象资料,应用MIDAS/FEA软件对秋季施工的13#桥墩建立了有限元模型,计算了出了墩身混凝土的温度场并对其进行了分析,并仿真模拟了墩身大体积混凝土的温度应力,对施工期间的大体积混凝土,探讨了其温度场的分布,并研究了其裂缝的开展原因,得到了在墩身大体积混凝土中,温度场是如何分布的、有什么规律,并得到了混凝土中的温度应力值,以及混凝土内部与表面的温度之差对温度应力的影响。然后分析这些结果之后,预测出由于过大的温度应力,而在墩身混凝土中引起裂缝,以及这些裂缝在墩身的哪些位置出现。接着,将有限元计算得的值与在现场实际测量数据进行对比,最后,改进了常规的温控措施,比如选择的材料,使用的浇筑方法、采取的养护措施等等,探讨了旱区铁路桥墩大体积混凝土施工的防裂技术对策,为今后同类桥梁墩台防裂施工和工法改进提供技术指导。具体内容如下:(1)针对在西北高原地区秋季施工的13#桥墩,使用MIDAS/FEA软件,建立了有限元模型,计算了出了墩身混凝土的温度场并对其进行了分析,并仿真模拟了墩身大体积混凝土的温度应力,对施工期间的大体积混凝土,探讨了其温度场的分布,并研究了其裂缝的开展原因,得到了在墩身大体积混凝土中,温度场和温度应力的分布和规律,并概括出了温度场和温度应力随着龄期的不断的变化情况。(2)整理现场实测数据,并对整理好的数据进行分析,用excel绘出在秋季施工的大体积混凝土中,混凝土的温度随时间的变化曲线。并根据整理好数据,利用在建筑施工中通常使用的热工经验公式,将墩身内部的最高温度和表面的温度进行了计算。(3)将MIDAS/FEA软件的计算值,与经验公式的计算值和现场的实测值进行对比,以验证和确保MIDAS/FEA分析计算的结果的正确性。(4)从影响混凝土温度和影响混凝土应力的因素的角度,研究了在西北高原地区秋季施工的条件下,不同的昼夜温差和不同的养护工法,具体是如何影响混凝土的温度场和应力场的,提出了在西北高原地区秋季施工养护时,应当留意哪些事项,并得出了一套适用于铁路桥墩大体积混凝土,在西北高原地区秋季施工的防裂技术措施。
[Abstract]:In the northwest plateau of our country, railways continue to emerge. These railways were built with many large piers and foundations. In mass concrete, the distribution of temperature field and temperature stress is very complex. However, in the northwest plateau of China, the temperature difference between day and night is very large, the climate is dry, relatively speaking, the climate is relatively special. Therefore, if mass concrete is constructed in such a special environment, the distribution of temperature field and the distribution of temperature stress will be more complicated, and mass concrete will be more likely to have cracks. As a result, the normal use and durability of mass concrete structures will be affected. In this paper, based on the construction and maintenance process of a double-track railway pier in the northwest plateau region and on the basis of on-the-spot temperature collection, combined with the meteorological data of the same period in the area, the finite element model of the 13 # pier constructed in autumn is established by using MIDAS/FEA software. The temperature field of concrete of pier body is calculated and analyzed, and the temperature stress of mass concrete of pier body is simulated. The distribution of temperature field of mass concrete during construction is discussed. The reason of crack development is studied, and the distribution and regularity of temperature field in mass concrete of pier body are obtained, and the temperature stress value in concrete is obtained. And the influence of the temperature difference between the interior and the surface of the concrete on the temperature stress. After analyzing these results, it is predicted that the cracks in the concrete of the pier are caused by the excessive temperature stress, and the location of the cracks in the pier body is also predicted. Finally, the conventional temperature control measures, such as the selected materials, the pouring method used, the maintenance measures and so on, are improved, and so on, and then the finite element calculation value is compared with the actual measured data in the field, and finally, the conventional temperature control measures are improved. This paper discusses the crack prevention technical countermeasures for mass concrete construction of railway piers in arid areas, and provides technical guidance for similar bridge pier and abutment crack prevention construction and improvement of construction method in the future. The concrete contents are as follows: (1) for the 13 # pier constructed in the northwest plateau area in autumn, the finite element model is established by using MIDAS/FEA software, and the temperature field of the pier concrete is calculated and analyzed. The thermal stress of mass concrete of pier body is simulated, and the temperature distribution of mass concrete during construction is discussed, and the reason of crack development is studied, and the results show that the temperature field of mass concrete is in the mass concrete of pier body, and the distribution of temperature field of mass concrete during construction is discussed, and the reason of crack development is studied. The distribution and regularity of temperature field and temperature stress are summarized, and the changes of temperature field and temperature stress along with age are summarized. (2) the field measured data are sorted out, and the finished data are analyzed. The variation curve of concrete temperature with time in mass concrete constructed in autumn is drawn by excel. Based on the data collected, the maximum temperature and surface temperature of the pier body are calculated by using the thermal experience formula commonly used in building construction. (3) the calculation value of the MIDAS/FEA software is given, and the results are as follows: (1) the maximum temperature of the pier body and the surface temperature of the pier body are calculated. In order to verify and ensure the correctness of the results obtained by MIDAS/FEA analysis, the results are compared with those calculated by empirical formula and measured on the spot. (4) from the angle of influencing the temperature of concrete and the factors that affect the stress of concrete, Under the condition of autumn construction in Northwest Plateau, different diurnal temperature difference and different maintenance methods are studied, and how to affect the temperature field and stress field of concrete is discussed, and the construction maintenance in autumn in Northwest Plateau area is put forward. What matters should be paid attention to and a set of crack prevention technical measures for mass concrete construction of railway piers in the autumn of northwest plateau area are obtained.
【学位授予单位】：兰州交通大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U445.57
本文编号：2472436
[Abstract]:In the northwest plateau of our country, railways continue to emerge. These railways were built with many large piers and foundations. In mass concrete, the distribution of temperature field and temperature stress is very complex. However, in the northwest plateau of China, the temperature difference between day and night is very large, the climate is dry, relatively speaking, the climate is relatively special. Therefore, if mass concrete is constructed in such a special environment, the distribution of temperature field and the distribution of temperature stress will be more complicated, and mass concrete will be more likely to have cracks. As a result, the normal use and durability of mass concrete structures will be affected. In this paper, based on the construction and maintenance process of a double-track railway pier in the northwest plateau region and on the basis of on-the-spot temperature collection, combined with the meteorological data of the same period in the area, the finite element model of the 13 # pier constructed in autumn is established by using MIDAS/FEA software. The temperature field of concrete of pier body is calculated and analyzed, and the temperature stress of mass concrete of pier body is simulated. The distribution of temperature field of mass concrete during construction is discussed. The reason of crack development is studied, and the distribution and regularity of temperature field in mass concrete of pier body are obtained, and the temperature stress value in concrete is obtained. And the influence of the temperature difference between the interior and the surface of the concrete on the temperature stress. After analyzing these results, it is predicted that the cracks in the concrete of the pier are caused by the excessive temperature stress, and the location of the cracks in the pier body is also predicted. Finally, the conventional temperature control measures, such as the selected materials, the pouring method used, the maintenance measures and so on, are improved, and so on, and then the finite element calculation value is compared with the actual measured data in the field, and finally, the conventional temperature control measures are improved. This paper discusses the crack prevention technical countermeasures for mass concrete construction of railway piers in arid areas, and provides technical guidance for similar bridge pier and abutment crack prevention construction and improvement of construction method in the future. The concrete contents are as follows: (1) for the 13 # pier constructed in the northwest plateau area in autumn, the finite element model is established by using MIDAS/FEA software, and the temperature field of the pier concrete is calculated and analyzed. The thermal stress of mass concrete of pier body is simulated, and the temperature distribution of mass concrete during construction is discussed, and the reason of crack development is studied, and the results show that the temperature field of mass concrete is in the mass concrete of pier body, and the distribution of temperature field of mass concrete during construction is discussed, and the reason of crack development is studied. The distribution and regularity of temperature field and temperature stress are summarized, and the changes of temperature field and temperature stress along with age are summarized. (2) the field measured data are sorted out, and the finished data are analyzed. The variation curve of concrete temperature with time in mass concrete constructed in autumn is drawn by excel. Based on the data collected, the maximum temperature and surface temperature of the pier body are calculated by using the thermal experience formula commonly used in building construction. (3) the calculation value of the MIDAS/FEA software is given, and the results are as follows: (1) the maximum temperature of the pier body and the surface temperature of the pier body are calculated. In order to verify and ensure the correctness of the results obtained by MIDAS/FEA analysis, the results are compared with those calculated by empirical formula and measured on the spot. (4) from the angle of influencing the temperature of concrete and the factors that affect the stress of concrete, Under the condition of autumn construction in Northwest Plateau, different diurnal temperature difference and different maintenance methods are studied, and how to affect the temperature field and stress field of concrete is discussed, and the construction maintenance in autumn in Northwest Plateau area is put forward. What matters should be paid attention to and a set of crack prevention technical measures for mass concrete construction of railway piers in the autumn of northwest plateau area are obtained.
【学位授予单位】：兰州交通大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U445.57
【参考文献】
相关硕士学位论文 前1条
1 朱秋菊;闸墩混凝土结构温度应力分析及其应用[D];郑州大学;2005年
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