ULTRASONIC NON-DESTRUCTIVE TESTING OF CONCRETE STRUCTURES COMPACTNESS UNDER CIRCUMSTANCES OF QINGHAI-TIBET PLATEAU
-
摘要: 青藏高原的环境条件限制常导致混凝土出现密实性缺陷问题,如何对混凝土的密实性缺陷进行精确的无损检测,是保障结构承载力及耐久性的关键。该文结合此前在西藏雅鲁藏布江藏木大桥与广西南宁实地开展的混凝土超声试验结果,基于不同气压下混凝土实体的超声波速计算模型,建立了以气压、水胶比为参数的混凝土实体部分超声波速计算模型;进一步对混凝土在不同孔隙率、缺陷条件、骨料分布情况条件下的超声波速进行了计算分析。揭示了孔隙率及缺陷条件对混凝土超声波速的影响规律及机理。研究了骨料分布占比对混凝土超声检测结果的影响规律,建立了混凝土整体超声波速的多因素计算模型,并提出了基于超声波速的混凝土密实性统计分析方法,可以为实际工程中混凝土结构密实性的超声无损检测结果分析提供理论依据。Abstract: The environmental conditions of Qinghai-Tibet Plateau lead to the problem of compactness defects in concrete. Accurate non-destructive testing of concrete compactness defects is the key to ensuring the bearing capacity and durability of the structure. In this study, one ultrasonic pulse velocity (UPV) calculation model was established for the concrete entity part with air pressure and water-cement ratio as calculation parameters upon the UPV calculation model of concrete entities under different air pressures and combined with the results of the previous concrete ultrasonic tests carried out on Zangmu Bridge of Yarlung Zangbo River in Tibet and Nanning of Guangxi; and further calculated and analysed the UPV of concrete under the conditions of different porosity, of defects, and of aggregate distribution to reveal the influence regularity and mechanism of porosity and defects on UPV of concrete, to study the influence rule of aggregate distribution proportion on ultrasonic test results of concrete, to establish a multi-factor calculation model for overall UPV of concrete, and to propose a statistical analysis method of concrete compactness based on UPV. It is hoped that this study can provide a theoretical basis for the analysis of ultrasonic non-destructive testing results of concrete structure compactness in practical engineering.
-
表 1 有限元仿真参数列表
Table 1. Parameters used in FE model
参数 值 材料 水泥砂浆 纵波速度/(m·s−1) 3950 密度/(kg·m−3) 2050 材料 石灰石 纵波速度/(m·s−1) 4400 密度/(kg·m−3) 2610 单元尺寸/mm 1 时间步长/s 0.1×10−6 序号 水胶比 水/(kg/m3) 水泥/(kg/m3) 砂/(kg/m3) 碎石(5 mm~20 mm)/(kg/m3) 减水剂/(%) 1 0.30 168 560 712 980 7.5 2 0.33 176 533 712 980 6.0 3 0.36 184 511 712 980 4.5 4 0.39 191 490 712 980 3.5 5 0.42 197 469 712 980 2.5 6 0.45 203 451 712 980 0.0 7 0.48 208 433 712 980 0.0 8 0.51 213 418 712 980 0.0 序号 高原环境 平原环境 孔隙率P/(%) 混凝土整体超声波速UPV/(m·s−1) 绝对密实条件下的固相超声波速$ {v_{\rm s}}$/(m·s−1) 孔隙率P/(%) 混凝土整体超声波速UPV/(m·s−1) 绝对密实条件下的固相超声波速$ {v_{\rm s} } $/(m·s−1) 1 9.96 4935 5342 13.2 4925 5171 2 10.30 4839 5229 18.9 4848 5086 3 13.20 4808 5193 18.9 4789 5022 4 9.84 4768 5146 15.4 4811 5046 5 − 4790 5171 − 4847 5085 6 − 4592 4939 − 4793 5026 7 − 4650 5007 − 4630 4847 8 − 4277 4569 − 4772 5003 -
[1] 王可怡, 范雁. 无损检测监测技术在广东科学中心的应用[J]. 工程力学, 2010, 27(增刊 1): 286 − 289.WANG Keyi, FAN Yan. Application of undamage detection and monitoring technology in Guangdong science center [J]. Engineering Mechanics, 2010, 27(Suppl 1): 286 − 289. (in Chinese) [2] 谢文高, 张怡孝, 刘爱荣, 等. 基于水下机器人与数字图像技术的混凝土结构表面裂缝检测方法[J]. 工程力学, 2022, 39(增刊 1): 64 − 70. doi: 10.6052/j.issn.1000-4750.2021.05.S010XIE Wengao, ZHANG Yixiao, LIU Airong, et al. Method for concrete surface cracking detection based on ROV and digital image technology [J]. Engineering Mechanics, 2022, 39(Suppl 1): 64 − 70. (in Chinese) doi: 10.6052/j.issn.1000-4750.2021.05.S010 [3] ANUGONDA P, WIEHN J S, TURNER J A. Diffusion of ultrasound in concrete [J]. Ultrasonics, 2001, 39(6): 429 − 435. doi: 10.1016/S0041-624X(01)00077-4 [4] 杨娜, 张翀, 李天昊. 基于无人机与计算机视觉的中国古建筑木结构裂缝监测系统设计[J]. 工程力学, 2021, 38(3): 27 − 39. doi: 10.6052/j.issn.1000-4750.2020.04.0263YANG Na, ZHANG Chong, LI Tianhao. Design of crack monitoring system for Chinese ancient wooden buildings based on UAV and CV [J]. Engineering Mechanics, 2021, 38(3): 27 − 39. (in Chinese) doi: 10.6052/j.issn.1000-4750.2020.04.0263 [5] 郑阳, 何存富, 周进节, 等. 超声Lamb波在缺陷处的二维散射特性研究[J]. 工程力学, 2013, 30(8): 236 − 243. doi: 10.6052/j.issn.1000-4750.2012.03.0181ZHENG Yang, HE Cunfu, ZHOU Jinjie, et al. 2D scattering characteristics of Lamb wave at defects [J]. Engineering Mechanics, 2013, 30(8): 236 − 243. (in Chinese) doi: 10.6052/j.issn.1000-4750.2012.03.0181 [6] 陈劲, 陈晓东, 赵辉, 等. 基于红外热成像法和超声波法的钢管混凝土无损检测技术的试验研究与应用[J]. 建筑结构学报, 2021, 42(增刊 2): 444 − 453. doi: 10.14006/j.jzjgxb.2021.S2.0052CHEN Jin, CHEN Xiaodong, ZHAO Hui, et al. Experimental research and application of non-destructive detecting techniques for concrete-filled steel tubes based on infrared thermal imaging and ultrasonic method [J]. Journal of Building Structures, 2021, 42(Suppl 2): 444 − 453. (in Chinese) doi: 10.14006/j.jzjgxb.2021.S2.0052 [7] 陈猛, 贾益铭, 陈耕野, 等. 轴压荷载下钢管钢筋混凝土损伤状态超声检测研究[J]. 工程力学, 2019, 36(10): 172 − 179. doi: 10.6052/j.issn.1000-4750.2018.10.0576CHEN Meng, JIA Yiming, CHEN Gengye, et al. Research on the damage condition of reinforced concrete filled steel tubes under axial load using ultrasonic testing [J]. Engineering Mechanics, 2019, 36(10): 172 − 179. (in Chinese) doi: 10.6052/j.issn.1000-4750.2018.10.0576 [8] 焦敬品, 钟茜, 王炯耿, 等. 窄板中超声导波传播特性试验研究[J]. 工程力学, 2013, 30(7): 255 − 261, 275. doi: 10.6052/j.issn.1000-4750.2012.02.0076JIAO Jingpin, ZHONG Xi, WANG Jionggeng, et al. On propagation characteristics of guided waves in narrowband [J]. Engineering Mechanics, 2013, 30(7): 255 − 261, 275. (in Chinese) doi: 10.6052/j.issn.1000-4750.2012.02.0076 [9] MALHOTRA V M, CARINO N J. Handbook on nondestructive testing of concrete [M]. 2nd ed. Boca Raton: CRC Press, 2003: 189 − 207. [10] YAMAN I O, AKTAN H M, HEARN N. Active and non-active porosity in concrete Part II: Evaluation of existing models [J]. Materials and Structures, 2002, 35(2): 110 − 116. doi: 10.1007/BF02482110 [11] 陈正, 陈犇, 郑皆连, 等. 青藏高原低气压环境下钢管混凝土的核心混凝土密实性评估方法研究[J]. 土木工程学报, 2021, 54(8): 1 − 13. doi: 10.15951/j.tmgcxb.2021.08.002CHEN Zheng, CHEN Ben, ZHENG Jielian, et al. Methodology on evaluating the compactness of core concrete in CFST serving under low atmospheric pressure over the Qinghai-Tibet Plateau [J]. China Civil Engineering Journal, 2021, 54(8): 1 − 13. (in Chinese) doi: 10.15951/j.tmgcxb.2021.08.002 [12] LAFHAJ Z, GOUEYGOU M, DJERBI A, et al. Correlation between porosity, permeability and ultrasonic parameters of mortar with variable water/cement ratio and water content [J]. Cement and Concrete Research, 2006, 36(4): 625 − 633. doi: 10.1016/j.cemconres.2005.11.009 -