高原鐵路橋墩大體積混凝土溫度場(chǎng)及溫度應(yīng)力分析
發(fā)布時(shí)間：2019-05-09 03:25
【摘要】：在我國(guó)的西北高原地區(qū),鐵路不斷涌現(xiàn)。這些鐵路在建造的時(shí)候采用了不少大體積的橋墩和基礎(chǔ)。而在大體積混凝土中,溫度場(chǎng)的分布和溫度應(yīng)力的分布都是特別復(fù)雜的。而在我國(guó)的西北高原地區(qū),白天和夜間的溫度之差非常大,氣候干旱,相對(duì)來說氣候比較特殊。因此大體積混凝土若是在這樣比較特殊的環(huán)境中施工,則其溫度場(chǎng)的分布和溫度應(yīng)力的分布相對(duì)來說就會(huì)更加復(fù)雜,大體積混凝土就更容易有裂縫產(chǎn)生,從而會(huì)導(dǎo)致大體積混凝土結(jié)構(gòu)的正常使用和耐久性受到影響。本文在西北高原地區(qū)某雙線鐵路橋墩施工、養(yǎng)護(hù)過程和在現(xiàn)場(chǎng)溫度采集的基礎(chǔ)上,結(jié)合當(dāng)?shù)赝瑫r(shí)期的氣象資料,應(yīng)用MIDAS/FEA軟件對(duì)秋季施工的13#橋墩建立了有限元模型,計(jì)算了出了墩身混凝土的溫度場(chǎng)并對(duì)其進(jìn)行了分析,并仿真模擬了墩身大體積混凝土的溫度應(yīng)力,對(duì)施工期間的大體積混凝土,探討了其溫度場(chǎng)的分布,并研究了其裂縫的開展原因,得到了在墩身大體積混凝土中,溫度場(chǎng)是如何分布的、有什么規(guī)律,并得到了混凝土中的溫度應(yīng)力值,以及混凝土內(nèi)部與表面的溫度之差對(duì)溫度應(yīng)力的影響。然后分析這些結(jié)果之后,預(yù)測(cè)出由于過大的溫度應(yīng)力,而在墩身混凝土中引起裂縫,以及這些裂縫在墩身的哪些位置出現(xiàn)。接著,將有限元計(jì)算得的值與在現(xiàn)場(chǎng)實(shí)際測(cè)量數(shù)據(jù)進(jìn)行對(duì)比,最后,改進(jìn)了常規(guī)的溫控措施,比如選擇的材料,使用的澆筑方法、采取的養(yǎng)護(hù)措施等等,探討了旱區(qū)鐵路橋墩大體積混凝土施工的防裂技術(shù)對(duì)策,為今后同類橋梁墩臺(tái)防裂施工和工法改進(jìn)提供技術(shù)指導(dǎo)。具體內(nèi)容如下:(1)針對(duì)在西北高原地區(qū)秋季施工的13#橋墩,使用MIDAS/FEA軟件,建立了有限元模型,計(jì)算了出了墩身混凝土的溫度場(chǎng)并對(duì)其進(jìn)行了分析,并仿真模擬了墩身大體積混凝土的溫度應(yīng)力,對(duì)施工期間的大體積混凝土,探討了其溫度場(chǎng)的分布,并研究了其裂縫的開展原因,得到了在墩身大體積混凝土中,溫度場(chǎng)和溫度應(yīng)力的分布和規(guī)律,并概括出了溫度場(chǎng)和溫度應(yīng)力隨著齡期的不斷的變化情況。(2)整理現(xiàn)場(chǎng)實(shí)測(cè)數(shù)據(jù),并對(duì)整理好的數(shù)據(jù)進(jìn)行分析,用excel繪出在秋季施工的大體積混凝土中,混凝土的溫度隨時(shí)間的變化曲線。并根據(jù)整理好數(shù)據(jù),利用在建筑施工中通常使用的熱工經(jīng)驗(yàn)公式,將墩身內(nèi)部的最高溫度和表面的溫度進(jìn)行了計(jì)算。(3)將MIDAS/FEA軟件的計(jì)算值,與經(jīng)驗(yàn)公式的計(jì)算值和現(xiàn)場(chǎng)的實(shí)測(cè)值進(jìn)行對(duì)比,以驗(yàn)證和確保MIDAS/FEA分析計(jì)算的結(jié)果的正確性。(4)從影響混凝土溫度和影響混凝土應(yīng)力的因素的角度,研究了在西北高原地區(qū)秋季施工的條件下,不同的晝夜溫差和不同的養(yǎng)護(hù)工法,具體是如何影響混凝土的溫度場(chǎng)和應(yīng)力場(chǎng)的,提出了在西北高原地區(qū)秋季施工養(yǎng)護(hù)時(shí),應(yīng)當(dāng)留意哪些事項(xiàng),并得出了一套適用于鐵路橋墩大體積混凝土,在西北高原地區(qū)秋季施工的防裂技術(shù)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.
【學(xué)位授予單位】：蘭州交通大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：U445.57
本文編號(hào)：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.
【學(xué)位授予單位】：蘭州交通大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：U445.57
【參考文獻(xiàn)】
相關(guān)碩士學(xué)位論文 前1條
1 朱秋菊;閘墩混凝土結(jié)構(gòu)溫度應(yīng)力分析及其應(yīng)用[D];鄭州大學(xué);2005年
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