本文選題：預應力混凝土結(jié)構(gòu)　切入點：海洋環(huán)境　出處：《江蘇大學》2017年碩士論文　論文類型：學位論文

【摘要】：預應力混凝土結(jié)構(gòu)以結(jié)構(gòu)性能好和經(jīng)濟效益高的優(yōu)點被大量用于海工混凝土結(jié)構(gòu)工程,然而結(jié)構(gòu)構(gòu)件在海水的長期浸泡和海洋環(huán)境侵蝕下耐久性問題日益突出。由于大型工程的建造對資源的消耗量極大,預應力混凝土結(jié)構(gòu)的耐久性問題已經(jīng)嚴重制約了我國可持續(xù)發(fā)展道路,受到了工程界的普遍關注。在國家自然科學基金資助項目“海工預應力混凝土結(jié)構(gòu)耐久性試驗相似理論探索與工程應用研究(51278230)”的資助下,本文針對海洋環(huán)境水下區(qū)預應力混凝土構(gòu)件在氯鹽侵蝕下的耐久性問題,基于混凝土中氯鹽侵蝕效應的相似性開展試驗研究,探索室內(nèi)模擬加速試驗構(gòu)件與現(xiàn)場結(jié)構(gòu)構(gòu)件之間氯鹽侵蝕效應的相似關系。主要內(nèi)容如下:1、完成服役結(jié)構(gòu)的現(xiàn)場檢測試驗,設計并完成室內(nèi)模擬加速試驗。對連云港墟溝港區(qū)69號泊位進行環(huán)境調(diào)查和耐久性檢測,根據(jù)調(diào)查及檢測結(jié)果,基于侵蝕效應相似,制定室內(nèi)模擬試驗的侵蝕制度,設計試驗室模擬加速的水下區(qū)混凝土結(jié)構(gòu)耐久性試驗,并對室內(nèi)試驗跟蹤檢測其侵蝕情況,結(jié)果表明室內(nèi)試驗與現(xiàn)場試驗具有高度相似性;2、分析試驗數(shù)據(jù),構(gòu)建環(huán)境與應力耦合作用下的環(huán)境-應力-時間相似模型。對現(xiàn)場試驗和室內(nèi)試驗的結(jié)果分別進行分析,發(fā)現(xiàn)氯離子濃度-時間曲線逐漸升高并趨于平緩,水膠比越大,試件氯離子濃度越大,氯離子擴散系數(shù)越大,在一定的應力水平內(nèi),氯離子濃度和氯離子擴散系數(shù)隨壓應力水平的增加而減小,基于相似理論由Fick第二定律擴散模型推導出環(huán)境與應力耦合作用下的環(huán)境-應力-時間相似模型,并根據(jù)試驗數(shù)據(jù)對相關系數(shù)進行修正;3、氯離子侵蝕后的預應力混凝土梁正截面受力性能試驗。根據(jù)工程結(jié)構(gòu)和環(huán)境狀況設計預應力混凝土梁并進行室內(nèi)模擬加速侵蝕試驗,在侵蝕一定時間后進行正截面承載力試驗,結(jié)果表明預應力梁在浸泡溶液中遭受侵蝕與混凝土養(yǎng)護的共同作用,混凝土強度等級為C40的試驗梁侵蝕效果顯著,承載力明顯降低,混凝土強度等級為C50的試驗梁在溶液中受到水的養(yǎng)護作用相比溶液侵蝕作用更加明顯,其承載力甚至有所提高;4、驗證環(huán)境-應力-時間相似模型,提出模型應用方法。針對連云港墟溝港區(qū)60號泊位在役結(jié)構(gòu),基于相似理論,制定室內(nèi)模擬加速試驗構(gòu)件,通過定期檢測加速試驗構(gòu)件的侵蝕狀況,模擬工程結(jié)構(gòu)的耐久性歷程,根據(jù)室內(nèi)模擬加速試驗與現(xiàn)場試驗的檢測結(jié)果,計算得到時間相似系數(shù)λ_t=10.95,氯離子侵蝕深度的相似系數(shù)λ_x=2.49。
[Abstract]:Prestressed concrete structures are widely used in marine concrete structures because of their good structural performance and high economic benefits. However, the durability of structural members is becoming more and more serious due to the long-term immersion of seawater and the erosion of marine environment. The durability of prestressed concrete structures has seriously restricted the sustainable development of our country. Under the support of the National Natural Science Foundation of China, the National Natural Science Foundation of China, supported by the National Natural Science Foundation of China, supported by the similar Theory Exploration and Engineering Application Research on the durability Test of Marine Prestressed concrete structures (51278230), Aiming at the durability of prestressed concrete members under chloride erosion in the underwater area of marine environment, based on the similarity of chloride erosion effect in concrete, the experimental study is carried out in this paper. To explore the similarity of chloride erosion effect between indoor simulated accelerated test components and field structural components. The main contents are as follows: 1. The indoor simulation accelerated test was designed and completed. The environmental investigation and durability test of berth 69 in Xugou Port area of Lianyungang were carried out. According to the results of investigation and test, based on the similar erosion effect, the erosion system of indoor simulation test was established. The durability test of concrete structure in underwater area is simulated and accelerated in the laboratory. The results show that the indoor test has a high similarity with the field test, and the test data are analyzed, and the results show that the indoor test has a high similarity with the field test. The environment-stress-time similarity model under the coupling of environment and stress was constructed. The results of field and laboratory tests were analyzed, and it was found that the concentration-time curve of chloride ion gradually increased and tended to be gentle, and the ratio of water to binder increased. The larger the chloride concentration, the greater the chloride diffusion coefficient. In a certain stress level, the chloride ion concentration and chloride diffusion coefficient decrease with the increase of compressive stress level. Based on the similarity theory, the environment-stress-time similarity model under the coupling of environment and stress is derived from the diffusion model of Fick's second law. According to the experimental data, the correlation coefficient is corrected and the stress behavior of the normal section of prestressed concrete beam after chloride ion erosion is tested. The prestressed concrete beam is designed according to the engineering structure and environmental conditions, and the indoor simulated accelerated erosion test is carried out. After a certain time of erosion, the bearing capacity of the normal section is tested. The results show that the concrete strength grade C40 of the test beam with concrete strength grade C40 has a remarkable erosion effect, and the bearing capacity is obviously reduced. The concrete strength grade C50 test beam is more obviously affected by water curing in solution than by solution erosion, and its bearing capacity is even increased by 4%, which verifies the environment-stress-time similarity model. According to the existing structure of No. 60 berth in Xugou Port area of Lianyungang, based on the similarity theory, the indoor simulated accelerated test components are developed, and the erosion status of accelerated test members is regularly detected. According to the results of indoor and field tests, the time similarity coefficient 位 _ T _ T _ (10.95) and the similarity coefficient of chloride ion erosion depth 位 _ (x _ x) _ (2.49) are calculated for simulating the durability history of engineering structures.
【學位授予單位】：江蘇大學
【學位級別】：碩士
【學位授予年份】：2017
【分類號】：TV332

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