本文選題：海洋環(huán)境 + 耐久性��； 參考：《天津大學(xué)》2014年碩士論文

【摘要】：通過(guò)調(diào)查研究,海洋環(huán)境下的許多混凝土結(jié)構(gòu)在還沒(méi)有達(dá)到預(yù)定的服役壽命前,就需要耗費(fèi)大量的資金對(duì)其進(jìn)行修護(hù)或重建,究其主要原因是多種海洋環(huán)境要素的共同作用加速了海水中氯離子在混凝土中侵蝕,導(dǎo)致鋼筋發(fā)生電化學(xué)腐蝕。目前,對(duì)于混凝土耐久性的研究仍處于經(jīng)驗(yàn)階段,干濕交替作用下的氯離子傳輸模型研究尚不完善。本文在綜合分析已有成果的基礎(chǔ)上,以氯離子傳輸機(jī)理為中心,建立了在材料性質(zhì)和環(huán)境要素的影響下,適用于海洋環(huán)境的氯離子傳輸模型。并且以江蘇東海海域的海上風(fēng)電場(chǎng)為工程背景,通過(guò)理論研究和數(shù)值分析,研究了處于水位變動(dòng)區(qū)的基礎(chǔ)薄壁結(jié)構(gòu)的氯離子侵蝕規(guī)律,具體內(nèi)容如下:1、分析混凝土結(jié)構(gòu)耐久性破壞的機(jī)理,研究影響氯離子傳輸和鋼筋腐蝕的材料性質(zhì),其中水灰比和保護(hù)層厚度是影響結(jié)構(gòu)壽命最關(guān)鍵的材料因素。2、將海洋環(huán)境多因素作用下的氯離子傳輸過(guò)程分解為溫度傳導(dǎo)、水分傳輸、氯離子擴(kuò)散和對(duì)流幾個(gè)子過(guò)程,分析各子過(guò)程的運(yùn)行機(jī)理、計(jì)算公式、發(fā)生條件和相互之間耦合作用,建立海洋環(huán)境下的氯離子傳輸模型。3、考慮太陽(yáng)輻射和潮汐水位變動(dòng)等因素影響下邊界條件的變化,利用有限差分方法對(duì)全壽命周期的溫度場(chǎng)、濕度場(chǎng)、氯離子濃度場(chǎng)進(jìn)行數(shù)值模擬分析,分析日照效應(yīng)和干濕循環(huán)對(duì)氯離子傳輸?shù)募铀僮饔谩?、應(yīng)用本模型分析氯離子侵蝕隨地理位置、朝向、高程的分布規(guī)律。位于低緯度地區(qū)的結(jié)構(gòu)日照能量吸收量是高緯度的3.08倍,朝陽(yáng)面的平均溫度比朝陰面高2.9℃,對(duì)流區(qū)的氯離子濃度隨高程升高呈先增大后減小的變化趨勢(shì)。5、對(duì)江蘇某海上風(fēng)電混凝土基礎(chǔ)結(jié)構(gòu)進(jìn)行耐久性評(píng)估,分析其各物理場(chǎng)的變化規(guī)律,并提出相應(yīng)的改善措施。
[Abstract]:Through investigation and research, many concrete structures in the marine environment need to spend a lot of money to repair or rebuild them before they reach their scheduled service life. The main reason is that the combined action of various marine environmental elements accelerates the corrosion of chloride ions in seawater and leads to electrochemical corrosion of steel bars. At present, the research on concrete durability is still in the experience stage, and the chloride transport model under the alternating action of dry and wet is not perfect. In this paper, based on the comprehensive analysis of the existing achievements and focusing on the mechanism of chloride ion transport, a chloride transport model suitable for marine environment is established under the influence of material properties and environmental factors. Taking the offshore wind farm in the East China Sea of Jiangsu Province as the engineering background, through theoretical research and numerical analysis, the chloride ion erosion law of the thin-walled foundation structure in the water level changing area is studied. The specific contents are as follows: 1. Analyze the mechanism of durability failure of concrete structures, study the properties of materials that affect chloride ion transport and corrosion of steel bars. The water-cement ratio and the thickness of the protective layer are the most important material factors affecting the life of the structure. The chlorine ion transport process under the action of many factors in the marine environment is decomposed into several sub-processes, such as temperature conduction, water transport, chloride ion diffusion and convection. The operation mechanism, calculation formula, occurrence condition and coupling action of each sub-process are analyzed, and the chlorine ion transport model .3 in marine environment is established. The variation of boundary conditions under the influence of solar radiation and tidal water level is taken into account. The finite difference method is used to simulate the temperature field, humidity field and chloride concentration field in the whole life cycle. The effect of sunlight and the accelerated effect of dry and wet cycle on chloride ion transport were analyzed. The distribution of chloride ion erosion with geographical location, orientation and elevation was analyzed by using this model. The solar energy absorption of the structure located in the low latitude is 3.08 times of that of the high latitude, and the average temperature of the morning sun is 2.9 鈩，

本文編號(hào)：1914557