本文選題：深凍結(jié)井 + 鋼筋混凝土井壁��； 參考：《合肥工業(yè)大學(xué)》2013年博士論文

【摘要】：大體積混凝土結(jié)構(gòu)由于溫度的變化會產(chǎn)生很大的拉應(yīng)力,要把這種由溫度變化而產(chǎn)生的拉應(yīng)力控制在允許范圍內(nèi),就需要對混凝土的溫度進行控制。影響控制混凝土溫度的變化因素較多,引起混凝土裂縫的機理也較為復(fù)雜,目前為止,依然難以準(zhǔn)確地模擬和預(yù)計各種多變因素對混凝土裂縫發(fā)生以及發(fā)展而產(chǎn)生的影響。本文以淮南礦業(yè)集團礦井井壁大體積高高性能混凝土為科學(xué)研究背景,首先從混凝土水化熱分析的理論出發(fā),闡述了熱傳導(dǎo)方程在混凝土裂縫控制中的應(yīng)用,求解熱力學(xué)所需要的邊界條件和初始條件,有限元分析的顯式與隱式解法,分析混凝土水化熱仿真分析所需要的熱力學(xué)參數(shù);在對混凝土熱力學(xué)參數(shù)進行確定之后,應(yīng)用ANSYS結(jié)構(gòu)熱力學(xué)有限元分析軟件熱單元SOLID70對該集礦井井壁溫度場、溫度應(yīng)力、應(yīng)變進行了仿真分析,通過理論分析、現(xiàn)場監(jiān)測、數(shù)值模擬研究探討了井壁混凝土在凍結(jié)工況條件下溫度場和應(yīng)力場的變化及分布規(guī)律。研究的主要內(nèi)容有： 1.對深凍結(jié)井井壁高強高性能混凝土的配合比進行了實驗室和現(xiàn)場試驗研究,在添加高效減水劑的前提條件下,通過使用三種礦物摻和料(粉煤灰、硅粉和磨細礦渣)技術(shù),研究配制的混凝土滿足了高強、早強的要求,同時還提高了混凝土的耐久性和后期強度。 2.依據(jù)凍土的物理力學(xué)性質(zhì)和混凝土水化熱特性,分析了凍結(jié)法施工鑿井井壁混凝土的不同組成成分對混凝土強度等性能的影響,研究了井壁混凝土放熱性能及水化熱的產(chǎn)生機理和理論分析方法。 3.結(jié)合凍結(jié)法施工鑿井施工過程,對井壁混凝土施工過程中溫度、應(yīng)力變化進行監(jiān)測與分析,得到了井壁和凍結(jié)壁溫度場分布變化規(guī)律,凍脹壓力變化規(guī)律和井壁鋼筋混凝土的受力規(guī)律。 4.對凍土進行室內(nèi)物理力學(xué)性能試驗研究,得出凍土比熱、導(dǎo)熱系數(shù)以及凍土力學(xué)基本參數(shù)。 5.混凝土水化熱溫升模型分別采用指數(shù)式、雙曲線式和復(fù)合指數(shù)式進行試算,將計算結(jié)果與實測平均溫度對比,確定了合適的的水化熱升溫模型。 6.考慮了混凝土水化放熱情況,建立了凍結(jié)法施工鑿井凍結(jié)壁井壁溫度場數(shù)值計算模型,運用有限元軟件ANSYS對凍結(jié)井壁溫度場進行計算,得到了凍結(jié)井壁溫度場分布變化特性。 7.導(dǎo)入溫度場計算結(jié)果,采用三種不同計算方案,對井壁溫度場應(yīng)進行有限元分析計算計算,得出井壁溫度應(yīng)力分布。
[Abstract]:Because the temperature of mass concrete structure will produce great tensile stress, it is necessary to control the temperature of concrete in order to control the tensile stress caused by temperature change within the allowable range. There are many factors that affect the temperature of concrete, and the mechanism of causing concrete cracks is complex. So far, it is still difficult to accurately simulate and predict the influence of various factors on the occurrence and development of concrete cracks. In this paper, based on the scientific research background of large-volume high performance concrete of mine shaft wall of Huainan Mining Group, the application of heat conduction equation in crack control of concrete is expounded based on the theory of hydration heat analysis of concrete. The boundary conditions and initial conditions for solving thermodynamics, explicit and implicit solutions for finite element analysis, and thermodynamic parameters for hydration heat simulation of concrete are analyzed. The thermal element SOLID70 is used to simulate and analyze the temperature field, temperature stress and strain of the shaft wall in this mine by ANSYS structural thermodynamics finite element analysis software. The variation and distribution of temperature field and stress field of wellbore concrete under freezing condition are studied by numerical simulation. The main contents of the study are as follows: 1. The mixture ratio of high strength and high performance concrete of deep freezing well wall was studied in laboratory and in situ. Under the precondition of adding high efficiency water reducing agent, three kinds of mineral admixtures (fly ash, silica fume and fine abrasive slag) were used. The concrete prepared by the study meets the requirements of high strength and early strength, and at the same time improves the durability and later strength of concrete. 2. 2. Based on the physical and mechanical properties of frozen soil and the hydration heat characteristics of concrete, the influence of different components of concrete on concrete strength and other properties of shaft lining in freezing construction is analyzed. The mechanism and theoretical analysis method of heat release performance and hydration heat of wellbore concrete are studied. Combined with the freezing construction process, the temperature and stress changes during the shaft lining concrete construction are monitored and analyzed, and the distribution and variation of the temperature field of the shaft wall and frozen wall are obtained. Variation of frost heave pressure and stress law of reinforced concrete on shaft lining. 4. The physical and mechanical properties of permafrost were studied in laboratory, and the specific heat, thermal conductivity and basic mechanical parameters of frozen soil were obtained. The hydration heat temperature rise model of concrete is calculated by exponential, hyperbolic and composite exponent respectively. The calculated results are compared with the measured average temperature, and the suitable hydration heat rise model is determined. 6. Considering the hydration heat release of concrete, the numerical calculation model of freezing wall temperature field in freezing construction is established, and the temperature field of frozen shaft wall is calculated by finite element software ANSYS. The variation characteristics of temperature field distribution of freezing shaft wall are obtained. 7. 7. According to the calculation results of temperature field and three different calculation schemes, the temperature field of shaft wall should be analyzed and calculated by finite element method, and the distribution of temperature stress of shaft wall should be obtained.
【學(xué)位授予單位】：合肥工業(yè)大學(xué)
【學(xué)位級別】：博士
【學(xué)位授予年份】：2013
【分類號】：TD352;TU375

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