-
摘要: 沉管隧道置于不易檢查和維護的海泥區域,其鋼殼結構受到海水的侵蝕,會縮短其服役周期,腐蝕嚴重則會影響沉管隧道的安全運行。深中通道(又稱“深中大橋”)是國內首個鋼殼式沉管隧道,耐久性要求100年,針對深中通道鋼殼混凝土沉管的服役環境及超高的耐久性要求等諸多特征,且目前國內外可以借鑒的工程和研究很少,因此需要研究揭示鋼殼外壁在海洋環境下的腐蝕機理和腐蝕發展規律。本文采用室內腐蝕模擬加速試驗及電化學分析測試等,對深中通道沉管隧道鋼殼所用Q390C低合金高強度結構鋼在模擬海水條件下的腐蝕發生發展規律進行研究。研究發現Q390C在海水中腐蝕產物主要為Fe3O4、α-FeOOH和γ-FeOOH及少量CaCO3,其均勻腐蝕和局部腐蝕速率都呈指數關系下降,最終趨于穩定。Abstract: China is rich in marine resources, and with the development of its economy and the improvement of its transportation level, the use of immersed tunnel technology is increasingly more extensive. The Shenzhen–Zhongshan Bridge is the first steel shell immersed tunnel in China. The immersed tunnel is located in a sea mud area that is not easy to inspect and maintain, and its steel shell structure is eroded by seawater, which shortens its service cycle, and severe corrosion affects its safe operation. Its durability requirement is 100 years. For the service environment and ultrahigh durability requirements of the Shenzhen–Zhongshan Bridge steel shell concrete immersed pipe and many other characteristics, at present, few engineering and research references at home and abroad can be used. Thus, the corrosion development law of the outer wall of an immersed steel shell in a marine environment must be studied and revealed. In this work, dissolved oxygen (15.2 mg·L–1) was artificially added to a simulated seawater solution as a depolarizing agent to realize the acceleration process of a corrosion simulation acceleration test in the laboratory. The test set cycle was 1, 7, 15, 30, 90, 180, and 365 d, and the test temperature was 25 ℃. Through the electrochemical impedance spectroscopy (EIS), the Tafel polarization curve, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), confocal laser scanning microscopy (CLSM), and other analytical and testing methods of samples with different test cycles, the corrosion occurrence and development law of Q390C low-alloy high-strength structural steel used in deep–medium channel immersed tunnel steel shells under simulated seawater conditions was studied. The corrosion products of Q390C steel in seawater are mainly found to be Fe3O4, α-FeOOH, γ-FeOOH, and a small amount of CaCO3, and their uniform corrosion and local corrosion rates decrease exponentially and eventually tend to stabilize. CLSM test shows that the surface of the specimen begins to corrode uniformly after a test cycle of 15 d, and the pitting corrosion pit depth of the specimen with a test cycle of 365 d can reach 99 μm. The long-term accelerated corrosion test of the steel shell of an immersed tunnel in seawater in this paper is of great importance to ensure the long-life durability of immersed tunnels in marine engineering and similar construction projects.
-
表 1 Q390C的化學成分( 質量分數)
Table 1. Chemical composition of Q390C
% C Si Mn S P Cr Ni Ti V Al Fe 0.20 0.50 1.70 0.03 0.03 0.30 0.50 0.05 0.13 0.015 Bal. 表 2 裸鋼試樣在不同試驗周期的腐蝕速率
Table 2. Corrosion rate of bare steel specimens at different test cycles
Test cycle/d Uniform corrosion rate/(mm·a–1) Local corrosion rate/(mm·a–1) 1 0.3039 — 7 0.1609 — 15 0.1452 0.3731 30 0.1291 0.3569 90 0.1088 0.1663 180 0.1022 0.1136 365 0.0819 0.0990 表 3 EIS擬合得到的電化學參數
Table 3. Electrochemical parameters obtained by EIS fitting
Test cycle/d Rp/(Ω·cm2) 1 1517 7 1235 15 831 30 723 90 1114 180 1223 365 2294 www.77susu.com -
參考文獻
[1] Jiang S P, Zhang E Q, Guo J, et al. Experimental research on fire protection for immersed tunnel joint. Chin J Undergr Space Eng, 2016, 12(3): 607蔣樹屏, 張恩情, 郭軍, 等. 沉管隧道接頭構件耐火試驗研究. 地下空間與工程學報, 2016, 12(3):607 [2] Chen Y. Application and developing trends of immersed tunnel. Tunn Constr, 2017, 37(4): 387陳越. 沉管隧道技術應用及發展趨勢. 隧道建設, 2017, 37(4):387 [3] Liu L F, Lin W, Yin H Q, et al. Construction of immersed tunnel engineering in the world and development status of immersed tunnel technology in China. China Harbour Eng, 2021, 41(8): 71劉凌鋒, 林巍, 尹海卿, 等. 世界交通沉管隧道工程建造情況與我國沉管科技發展現狀. 中國港灣建設, 2021, 41(8):71 [4] Song H S, Chen X Y, Liang Z X, et al. Development and application of measurement software for steel shell of immersed tunnel based on Python. Yangtze River, 2020, 51(9): 223 doi: 10.16232/j.cnki.1001-4179.2020.09.039宋華山, 陳向陽, 梁柱信, 等. 基于Python的沉管鋼殼測量軟件開發與應用. 人民長江, 2020, 51(9):223 doi: 10.16232/j.cnki.1001-4179.2020.09.039 [5] Lu M, Zhu Z X. Optimization and discussion of waterproofing and anti - corrosion design of immersed tunnel. China Build Waterproofing, 2010(2): 13 doi: 10.3969/j.issn.1007-497X.2010.02.005陸明, 朱祖熹. 沉管隧道防水防腐設計的優化及其探討. 中國建筑防水, 2010(2):13 doi: 10.3969/j.issn.1007-497X.2010.02.005 [6] Deep channel immersed tunnel-the world’s first large-scale immersed tunnel with steel-shell concrete composite structure. Tunn Rail Transit, 2020(4): 64深中通道沉管隧道—世界首條大規模采用鋼殼混凝土組合結構的沉管隧道. 隧道與軌道交通, 2020(4): 64 [7] Zhao Y T. Song S Y, Wang X C, et al. Subsea structure sacrificial anode protection mold experiment and simulation calculation // Summary of the 10th National Corrosion Conference. Nanchang, 2019: 237趙永韜, 宋神友, 汪相辰, 等. 海底結構犧牲陽極保護物模實驗和仿真計算. 第十屆全國腐蝕大會摘要集. 南昌, 2019: 237 [8] Zhao Y T. Song S Y, Yin X T, et al. Submarine structure sacrificial anode protector mold experiment and simulation calculation // Summary Collection of the 7th Marine Materials and Corrosion Protection Conference 2020 and the 1st Reinforced Concrete Durability and Facility Service Safety Conference 2020. Wuxi, 2020: 1趙永韜, 宋神友, 尹學濤, 等. 沉管鋼殼犧牲陽極保護數值模擬驗證和修正. 2020第七屆海洋材料與腐蝕防護大會暨2020第一屆鋼筋混凝土耐久性與設施服役安全大會摘要集. 無錫, 2020: 1 [9] Niu X L, Chen C P. Research progress of corrosion protection of steel structure in marine engineering. Ship Eng, 2019, 41(4): 100 doi: 10.13788/j.cnki.cbgc.2019.04.18牛雪蓮, 陳昌平. 海洋工程鋼結構腐蝕防護的研究進展. 船舶工程, 2019, 41(4):100 doi: 10.13788/j.cnki.cbgc.2019.04.18 [10] Cao C N. Natural Environment Corrosion of Materials in China. Beijing: Chemical Industry Press, 2005曹楚南. 中國材料的自然環境腐蝕. 北京: 化學工業出版社, 2005 [11] Zhu X R, Wang X R. Corrosion and Protection of Metals in Marine Environment. Beijing: National Defense Industry Press, 1999朱相榮, 王相潤. 金屬材料的海洋腐蝕與防護. 北京: 國防工業出版社, 1999 [12] Hou B R. Marine Corrosion and Protection. Beijing: Science Press, 1997侯保榮. 海洋腐蝕與防護. 北京: 科學出版社, 1997 [13] Jin W X, Luo Y N, Song S Z. Marine erosion-corrosion detections of metal materials. J Chin Soc Corros Prot, 2008, 28(6): 337 doi: 10.3969/j.issn.1005-4537.2008.06.004金威賢, 雒婭楠, 宋詩哲. 金屬材料實海沖刷腐蝕檢測. 中國腐蝕與防護學報, 2008, 28(6):337 doi: 10.3969/j.issn.1005-4537.2008.06.004 [14] Chen H L, Wei Y. Corrosion mechanism of a carbon steel in simulated humid atmospheres. Corros Sci Prot Technol, 2006, 18(4): 255 doi: 10.3969/j.issn.1002-6495.2006.04.006陳惠玲, 魏雨. 一種碳鋼在模擬潮濕環境中腐蝕機理的探討. 腐蝕科學與防護技術, 2006, 18(4):255 doi: 10.3969/j.issn.1002-6495.2006.04.006 [15] Xiao K, Dong C F, Li X G, et al. Study on accelerated corrosion tests for carbon steels and weathering steels. Equip Environ Eng, 2007, 4(3): 5 doi: 10.3969/j.issn.1672-9242.2007.03.002肖葵, 董超芳, 李曉剛, 等. 碳鋼和耐候鋼加速腐蝕實驗研究. 裝備環境工程, 2007, 4(3):5 doi: 10.3969/j.issn.1672-9242.2007.03.002 [16] Zhong W B. Development of steel plate for bridge and tunnel for Shenzhen-Zhongshan Bridge in Baosteel. Baosteel Technol, 2022(2): 65鐘武波. 寶鋼供深中通道橋隧用鋼板的開發. 寶鋼技術, 2022(2):65 [17] Zhao H, Li Q, Zhang J. Study on low temperature welding technology of steel structure Q390C. J New Ind, 2020, 10(1): 80 doi: 10.19335/j.cnki.2095-6649.2020.01.018趙輝, 李強, 張佳. 鋼結構Q390C低溫焊接工藝研究. 新型工業化, 2020, 10(1):80 doi: 10.19335/j.cnki.2095-6649.2020.01.018 [18] Lu Q K, Wang L W, Xin J C, et al. Corrosion evolution and stress corrosion cracking of E690 steel for marine construction in artificial seawater under potentiostatic anodic polarization. Constr Build Mater, 2020, 238: 117763 doi: 10.1016/j.conbuildmat.2019.117763 [19] ASTM International, ASTM D1141–98(2021) Standard Practice for Preparation of Substitute Ocean Water. United States: ASTM International, 2021 [20] Zhang H X, Zeng H B, Qiu R. Main influencing factors to accelerate low alloy steel corrosion in seawater by adding H2O2. Equip Environ Eng, 2012, 9(6): 47張慧霞, 曾華波, 邱日. 添加H2O2加速低合金鋼海水腐蝕的主要影響因素研究. 裝備環境工程, 2012, 9(6):47 [21] Liu Z G, Gao X H, Du L X, et al. Corrosion behavior of armor layer steel of flexible pipes exposed to seawater environment. J Northeast Univ (Nat Sci), 2017, 38(8): 1088 doi: 10.12068/j.issn.1005-3026.2017.08.006劉珍光, 高秀華, 杜林秀, 等. 海洋軟管鎧裝層用鋼的海水腐蝕行為. 東北大學學報(自然科學版), 2017, 38(8):1088 doi: 10.12068/j.issn.1005-3026.2017.08.006 [22] Metal Standardization Internet. GB/T16545–2015 Corrosion of Metals and Alloys-Removal of Corrosion Products from Corrosion Test Specimens. Beijing: Standards Press of China, 2015全國鋼標準化技術委員會. GB/T16545–2015金屬和合金的腐蝕 腐蝕試樣上腐蝕產物的清除. 北京: 中國標準出版社, 2015 [23] Wang X, Xiao K, Cheng X Q, et al. Corrosion prediction model of Q235 steel in polluted marine atmospheric environment. J Mater Eng, 2017, 45(4): 51 doi: 10.11868/j.issn.1001-4381.2015.001414王旭, 肖葵, 程學群, 等. Q235鋼的污染海洋大氣環境腐蝕壽命預測模型. 材料工程, 2017, 45(4):51 doi: 10.11868/j.issn.1001-4381.2015.001414 [24] Gu M B. An lnvesigation in corrosion of low-alloy steel in marine environment. Dev Appl Mater, 2012, 27(1): 40 doi: 10.3969/j.issn.1003-1545.2012.01.010谷美邦. 海洋環境下低合金鋼腐蝕行為研究. 材料開發與應用, 2012, 27(1):40 doi: 10.3969/j.issn.1003-1545.2012.01.010 [25] Mao C L, Xiao K, Dong C F, et al. Corrosion behavior of extra deep drawing cold rolled sheet in stimulative ocean-atmosphere environment. J Chin Soc Corros Prot, 2017, 37(2): 101 doi: 10.11902/1005.4537.2016.202毛成亮, 肖葵, 董超芳, 等. 超深沖壓用冷軋板在模擬海洋大氣環境中的腐蝕行為. 中國腐蝕與防護學報, 2017, 37(2):101 doi: 10.11902/1005.4537.2016.202 [26] Xu J W. Research on Key Corrosion Factors and Synergistic Mechanism of Q345 Steel in South China Sea [Dissertation]. Chongqing: Chongqing Jiaotong University, 2020徐靜雯. Q345鋼南海環境關鍵腐蝕因子及其協同作用機理研究[學位論文]. 重慶: 重慶交通大學, 2020 [27] Ding G Q, Li X Y, Zhang B, et al. Variation of free corrosion potential of several metallic materials in natural seawater. J Chin Soc Corros Prot, 2019, 39(6): 543 doi: 10.11902/1005.4537.2019.233丁國清, 李向陽, 張波, 等. 金屬材料在天然海水中的腐蝕電位及其變化規律. 中國腐蝕與防護學報, 2019, 39(6):543 doi: 10.11902/1005.4537.2019.233 [28] Su L L. Study on Corrosion Mechanism of Q235 Steel and Stainless Steel in Natural Seawater [Dissertation]. Jinan: Shandong University, 2010蘇璐璐. Q235鋼和不銹鋼海水腐蝕機理研究[學位論文]. 濟南: 山東大學, 2010 -