本文選題：LNG儲(chǔ)罐 + 溫度應(yīng)力��； 參考：《哈爾濱工業(yè)大學(xué)》2014年碩士論文

【摘要】：由于能源結(jié)構(gòu)的轉(zhuǎn)變及能源供應(yīng)、儲(chǔ)備的需要，大型預(yù)應(yīng)力混凝土液化天然氣(LNG)儲(chǔ)罐在我國的建造日益興起。目前，國內(nèi)對(duì)于此類型儲(chǔ)罐的設(shè)計(jì)、建造技術(shù)還未完全掌握，且LNG項(xiàng)目的投資金額巨大，如果能實(shí)現(xiàn)國內(nèi)自主設(shè)計(jì)及建造施工，將會(huì)帶來極大的經(jīng)濟(jì)效益。在已有的國內(nèi)儲(chǔ)罐建造工程中，混凝土外罐在施工期間極易出現(xiàn)裂縫，且儲(chǔ)罐的混凝土穹頂施工安全問題引起建造、設(shè)計(jì)者的重點(diǎn)關(guān)注，為此，本文以一座160000m3大型LNG預(yù)應(yīng)力全容罐為研究對(duì)象，以大型有限元分析軟件ANSYS為平臺(tái)，建立了精細(xì)化的有限元模型，精確地模擬了LNG儲(chǔ)罐混凝土外罐罐壁及穹頂?shù)膶?shí)際施工過程，具體研究工作如下： 1.按實(shí)際結(jié)構(gòu)施工順序與時(shí)間，模擬了LNG儲(chǔ)罐混凝土外罐罐壁全部混凝土澆筑過程；考慮隨時(shí)間變化的環(huán)境溫度，獲得了由水化熱作用產(chǎn)生的混凝土外罐早期溫度場分布；在考慮混凝土收縮和徐變的條件下，采用增量法計(jì)算了混凝土外罐的早期溫度應(yīng)力；確定了隨時(shí)間及配筋率變化的混凝土早期抗拉強(qiáng)度，通過與溫度應(yīng)力進(jìn)行對(duì)比，對(duì)LNG儲(chǔ)罐混凝土外罐施工階段的裂縫分布規(guī)律進(jìn)行了預(yù)測。研究結(jié)果表明：混凝土收縮對(duì)溫度應(yīng)力影響顯著，在150天的模擬時(shí)間段內(nèi)，結(jié)構(gòu)溫度應(yīng)力呈現(xiàn)持續(xù)增長狀態(tài)；LNG外罐第1澆筑段的溫度應(yīng)力明顯大于其他澆筑段的溫度應(yīng)力，且該澆筑段的罐壁在模擬期內(nèi)將產(chǎn)生豎向裂縫、扶壁柱處將產(chǎn)生局部環(huán)向裂縫； 2.分別探討了施工模板材料、施工質(zhì)量、施工季節(jié)及入模溫度對(duì)混凝土外罐溫度應(yīng)力的影響及其規(guī)律，結(jié)果顯示：模板對(duì)溫度應(yīng)力的影響作用較小，，施工質(zhì)量及施工季節(jié)對(duì)溫度應(yīng)力的影響較大。在此基礎(chǔ)上，將溫度應(yīng)力結(jié)果按各影響因素的作用進(jìn)行拆解，視溫度應(yīng)力結(jié)果為水化熱、混凝土收縮、外界氣溫及入模溫度各自單一影響作用下溫度應(yīng)力的疊加，進(jìn)而總結(jié)出了以調(diào)節(jié)施工季節(jié)為主，提高施工質(zhì)量為輔的結(jié)構(gòu)抗裂措施建議； 3.針對(duì)穹頂混凝土施工的支承模板結(jié)構(gòu)－帶鋼板肋環(huán)型鋼網(wǎng)殼，提出合理的穩(wěn)定性分析方案，并對(duì)其進(jìn)行非線性全過程穩(wěn)定性研究；探討了蒙皮鋼板厚度、網(wǎng)殼桿件截面尺寸、矢跨比、初始幾何缺陷形式及大小對(duì)帶鋼板網(wǎng)殼穩(wěn)定性能的影響規(guī)律； 4.根據(jù)儲(chǔ)罐穹頂混凝土澆筑的各個(gè)施工過程，分別建立相應(yīng)的有限元分析模型，確定各施工段的施工氣壓，獲得在相應(yīng)施工氣壓及初始缺陷下的網(wǎng)殼結(jié)構(gòu)安全系數(shù)，并對(duì)帶鋼板肋環(huán)型網(wǎng)殼結(jié)構(gòu)進(jìn)行優(yōu)化設(shè)計(jì)。
[Abstract]:Due to the transformation of energy structure and the need of energy supply and reserve, the construction of large prestressed concrete liquefied natural gas (LNG) storage tank is rising in our country. At present, the design and construction technology of this type of storage tank have not been fully grased at home, and the investment amount of the LNG project is huge, if the domestic design and construction can be realized, It will bring great economic benefit. In the existing domestic storage tank construction project, the concrete outer tank is very easy to crack during the construction period, and the construction safety problem of the concrete dome of the storage tank causes construction. The designer pays attention to it. For this reason, this paper takes a large 160000m3 large LNG prestressed full tank as the research object, with large finite element. The analysis software ANSYS is used as a platform to establish a finite-element model, which accurately simulates the actual construction process of the wall and dome of the LNG tank concrete tank. The specific research work is as follows:
1. according to the construction sequence and time of the actual structure, the concrete pouring process of the concrete outer tank wall of the LNG storage tank is simulated. Considering the time changing environment temperature, the early temperature field distribution of the concrete outer tank produced by the hydration heat is obtained, and the concrete is calculated by incremental method under the conditions of concrete shrinkage and change. The early temperature stress of the external tank is determined, and the early tensile strength of concrete with the change of time and reinforcement ratio is determined. Through the comparison with the temperature stress, the crack distribution in the construction stage of the LNG tank concrete tank is predicted. The results show that the concrete shrinkage has a significant influence on the temperature stress and in the 150 day simulation time period. The temperature stress of the structure of the structure in the LNG tank first is obviously greater than that of the other casting sections, and the wall of the casting section will produce a vertical crack during the simulation period, and the local circumferential crack will be produced at the buttress column.
2. the influence and regularity of construction template material, construction quality, construction season and mold temperature on the temperature stress of concrete tank are discussed. The results show that the effect of template on temperature stress is small, construction quality and construction season have great influence on temperature stress. On this basis, the results of temperature stress are affected by various factors. The effect is dismantled, and the result of temperature stress is hydration heat, concrete shrinkage, the superposition of temperature stress under the single influence of external temperature and mold temperature, and then the suggestion of structural anti cracking measures is summed up by adjusting the construction season and improving the construction quality.
3. in view of the support template structure of the dome concrete construction - steel ribbed steel reticulated reticulated shell with steel plate, a reasonable stability analysis scheme is put forward, and the stability of the nonlinear whole process is studied. The thickness of the skin plate, the section size of the reticulated shell, the vector span ratio, the initial geometric defect form and the size of the steel reticulated shell with steel plate are discussed. The law of influence;
4. according to the construction process of concrete pouring in the storage tank dome, the corresponding finite element analysis model is established respectively, the construction pressure of each construction section is determined, the safety coefficient of the reticulated shell structure under the corresponding construction pressure and initial defects is obtained, and the structure of the ribbed ring reticulated shell with steel plate is optimized.

【學(xué)位授予單位】：哈爾濱工業(yè)大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2014
【分類號(hào)】：TU375

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