本文選題：大體積混凝土　切入點：承臺　出處：《山東大學(xué)》2015年碩士論文　論文類型：學(xué)位論文

【摘要】：大體積混凝土構(gòu)件在水利工程中具有廣泛的應(yīng)用,隨著我國橋梁結(jié)構(gòu)對跨越能力要求的提高,大體積混凝土構(gòu)件越來越多的出現(xiàn)在橋梁工程建設(shè)中。橋梁工程與水利工程有所不同,大體積混凝土構(gòu)件更多的以橋梁承臺、零號塊或者斜拉橋橋塔等結(jié)構(gòu)形式出現(xiàn)。大體積混凝土構(gòu)件在使用過程中需要克服的問題是其水化過程中易于開裂的特性,由于自身體積較大,在水化放熱過程中會引起的較大的內(nèi)外溫差,如果控制不當很容易引起裂縫。裂縫會引起一系列次生病害,例如后期鋼筋銹蝕、混凝土腐蝕、耐久性降低、壽命下降等等。本文以西部某120米主跨連續(xù)剛構(gòu)橋為工程背景,以現(xiàn)場測試數(shù)據(jù)為基礎(chǔ),結(jié)合數(shù)值模型,對大體積混凝土承臺溫度效應(yīng)規(guī)律進行分析總結(jié)。并以此為基礎(chǔ),對大體積混凝土溫度場的各種影響因素進行分析研究。本文主要工作如下：1)首先列舉了國內(nèi)外學(xué)者對于混凝土水化熱原理以及施工現(xiàn)場溫度控制措施的研究現(xiàn)狀,介紹了混凝土溫度效應(yīng)計算參數(shù)以及分析原理；分析混凝土徐變影響因素,給出常用的徐變預(yù)測模型。2)調(diào)查橋梁現(xiàn)場工程概況,給出現(xiàn)場地質(zhì)水文資料、氣象環(huán)境參數(shù),為數(shù)值分析提供基礎(chǔ)。測試承臺水化熱溫度數(shù)據(jù),結(jié)合數(shù)值分析結(jié)果,分析混凝土水化熱分布規(guī)律,并檢驗數(shù)值模型的可靠性。3)通過現(xiàn)場數(shù)據(jù)測試,作出承臺內(nèi)部溫度變化曲線,采集出水口溫度變化規(guī)律并且對數(shù)據(jù)進行平滑處理,推導(dǎo)承臺合理拆模時機計算方法。根據(jù)該計算方法提出承臺合理拆模時機,為相同參數(shù)的后續(xù)承臺施工提供參考。4)以數(shù)值模型為基礎(chǔ),開展參數(shù)分析,以通水流量、水溫、水管管徑等為分析對象,探討其對混凝土溫控效果的影響；分析混凝土澆筑溫度變化和外部保溫措施對于構(gòu)件應(yīng)力分布狀態(tài)的影響,為現(xiàn)場溫控措施提供參考。5)針對橋梁所在區(qū)域經(jīng)常出現(xiàn)的寒潮和晝夜溫差,開展參數(shù)分析,歸納總結(jié)寒潮強度以及對流系數(shù)與混凝土表面應(yīng)力的關(guān)系。提出臨界降溫幅度和能夠抵消寒潮不利影響的臨界等效對流系數(shù),為現(xiàn)場保溫提供參考。
[Abstract]:Mass concrete members are widely used in water conservancy projects. More and more mass concrete members appear in the construction of bridge engineering. Structural forms such as zero block or cable-stayed bridge tower appear. The problem that mass concrete members need to overcome in the process of use is that they are prone to cracking during hydration, because of their large size, Large internal and external temperature differences during hydration and heat release can easily lead to cracks if they are not properly controlled. Cracks can cause a series of secondary diseases, such as corrosion of reinforcement in the later stage, corrosion of concrete, and reduced durability. Taking a 120m main span continuous rigid frame bridge in the west of China as engineering background, based on field test data and numerical model, the temperature effect law of mass concrete cap is analyzed and summarized in this paper. The main work of this paper is as follows: firstly, the research status of domestic and foreign scholars on the principle of hydration heat of concrete and the temperature control measures in construction site are listed. This paper introduces the calculation parameters and analysis principle of concrete temperature effect, analyzes the influencing factors of concrete creep, gives the commonly used creep prediction model. Testing cap hydration heat temperature data, combining the results of numerical analysis, analyzing the distribution law of concrete hydration heat, and checking the reliability of numerical model. According to the curve of inner temperature change of the cap, the rule of temperature change of the outlet and the smooth processing of the data, the calculating method of the reasonable time of removing the mould of the cap is deduced. According to the calculation method, the reasonable time of removing the mould of the cap is put forward. Based on numerical model, parameter analysis is carried out, and the effects of water flux, water temperature and pipe diameter on the effect of temperature control of concrete are discussed. This paper analyzes the influence of concrete pouring temperature change and external heat preservation measures on the stress distribution of concrete members, and provides a reference for the field temperature control measures. 5) in view of the cold wave and diurnal temperature difference that often occur in the bridge area, the parameter analysis is carried out. The relationship between cold wave intensity and convection coefficient and concrete surface stress is summarized. The critical cooling range and critical equivalent convection coefficient, which can counteract the adverse effects of cold wave, are put forward to provide reference for field heat preservation.
【學(xué)位授予單位】：山東大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：U445.57

【引證文獻】

相關(guān)會議論文 前1條

1 劉有志;張國新;劉毅;;特高拱壩施工期裂縫成因分析與溫控防裂方法新思路[A];北京力學(xué)會第17屆學(xué)術(shù)年會論文集[C];2011年

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本文編號：1562409