A new method for nondestructive testing of mudstone moisture migration process by nuclear magnetic resonance
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摘要: 利用传统方法测试岩土体内水分迁移时，往往要将原状土破碎和重塑，这会改变岩土体的结构，影响测试结果的真实性。利用核磁共振(NMR)技术具有无损测量材料中水分的特点，提出了一种新的测试方法。首先进行标定试验，将岩土试样放置在0~0.05 T的非均匀磁场中用不同的磁场强度测试，获得NMR信号量和试样水含量间的函数关系；然后对土样进行一维入渗试验与NMR测试，记录入渗时间、入渗水质量和不同位置条件下试样的NMR信号量；最后，根据标定试验所得NMR信号量与水含量之间的函数关系，计算获得试样中水分的空间分布。采用烘干法进行验证，试验结果与理论结果最大误差为4.05 %。Abstract: When traditional methods are used to test soil moisture migration of rock and soil, the undisturbed soil is often broken and reshaped, which will change the structure of rock and soil and affect the authenticity of the test results. In order to solve this problem, a new testing method is proposed by using the characteristics of nuclear magnetic resonance(NMR)technology for nondestructive measurement of moisture in materials. Firstly, the calibration experiment was carried out to establish a functional relationship between the NMR signal amplitude and the position of a soil sample with unit water mass in a non-uniform magnetic field of 0~0.05 T. Second, a one-dimensional infiltration experiment and NMR test were conducted to record the infiltration time, water mass increase and NMR signal under different test positions. Then, using the functional relationship obtained in the calibration experiment, approximations of the moisture mass and its spatial distribution in the sample were obtained by comparing the theoretical signal and the measured signals. Finally, the mudstone sample was cut into several parts to perform a verification experiment by oven drying, and the results showed that the error in water content was 4.05 % or less.
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Key words:
- water migration /
- nondestructive testing /
- nuclear magnetic resonance /
- mudstone
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图 3 在均匀磁场与非均匀磁场中的不同位置对试样进行测试
Figure 3. Test the sample at different positions in the uniform and non-uniform magnetic field
图 4 标定试样在磁场均匀和非均匀区的信号量实测值及其拟合曲线
Figure 4. The measured signal amplitude of the calibration sample in the uniform and non-uniform magnetic field and its fitting curve
图 5 不同测试位置的横向弛豫时间T2的分布
Figure 5. Distribution of the transverse relaxation time T2 at different test positions
图 8 试样在各次测试中的横向弛豫时间分布
Figure 8. Transverse relaxation time distribution of the sample in each test
图 9 理论信号量与实测信号量对比
Figure 9. Comparison between the calculated signal amplitudes and measured amplitudes
图 10 长条形土柱中含水率的空间分布
Figure 10. Spatial distribution of water content in long soil column
表 1 矿物X-射线衍射分析结果
Table 1. Mineral X-ray diffraction analysis
全岩矿物相对含量/% 黏土矿物相对含量/% 石英 斜长石 微斜长石 黏土总量 I/S It Kao C 33 9 6 52 80 15 3 2 注：S为蒙脱石，It为伊利石，C为绿泥石，Kao为高岭石，I/S为伊蒙混层。 
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表 2 参数a与含水率w之间的关系
Table 2. The relationship between a and w
a 5 011 4 605 4 363 4 135 w/% 10 18 25 31
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表 3 烘干泥岩试样在各测试位置的初始信号量
Table 3. The initial signal amplitude of dry mudstone samples at each test position
测试位置/mm 0 8 16 24 32 40 初始信号量 1 461 1 456 1 405 1 191 872 546
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表 4 水分迁移试验数据
Table 4. Test data of moisture migration
测试时间/h 试样总质量/g 试样中水的质量/g 0 5.988 0 0 24 6.612 0 0.624 0 48 7.085 3 1.097 3 72 7.496 5 1.508 5 120 7.816 7 1.828 7
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表 5 烘干法测试结果与NMR测试结果
Table 5. Drying method and NMR test results
土柱分层 质量/g 烘干后试样的质量/g 土柱中水的质量/g NMR信号换算的水质量/g 误差/% 1 1.544 4 0.989 8 0.554 6 0.577 1 4.05 2 1.335 4 0.998 1 0.337 3 0.346 3 2.67 3 1.263 3 0.996 0 0.267 3 0.277 0 3.64 4 1.252 9 1.006 2 0.246 7 0.249 3 1.05 5 1.196 8 1.002 9 0.193 9 0.199 4 2.85 6 1.182 0 0.995 0 0.187 0 0.179 5 -3.99
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[1] 陈汉青, 程桦, 曹璐, 等. 土/岩体的冻融回滞及水分迁移综合机制研究[J]. 岩石力学与工程学报, 2022, 41(11): 2365-2375. https://www.cnki.com.cn/Article/CJFDTOTAL-YSLX202211016.htmChen Hanqing, Cheng Hua, Cao Lu, et al. Research on the comprehensive mechanism of freeze-thaw hysteresis and water migration of soil/rock[J]. Chinese Journal of Rock Mechanics and Engineering, 2022, 41(11): 2365-2375. https://www.cnki.com.cn/Article/CJFDTOTAL-YSLX202211016.htm [2] 崔宏环, 闫利, 赵嘉. 高铁路基水泥粉煤灰填料冻融特性研究[J]. 铁道科学与工程学报, 2022, 19(10): 2785-2793. https://www.cnki.com.cn/Article/CJFDTOTAL-CSTD202210001.htmCui Honghuan, Yan Li, Zhao Jia. Study on freeze-thaw characteristics of cement fly ash filler for high-speed railway subgrade[J]. Journal of Railway Science and Engineering, 2022, 19(10): 2785-2793. https://www.cnki.com.cn/Article/CJFDTOTAL-CSTD202210001.htm [3] 于钱米, 邰博文, 牛吉强, 等. 细粒土空间不均匀分布对水分迁移的影响[J]. 中南大学学报: 自然科学版, 2020, 51(12): 3503-3514. https://www.cnki.com.cn/Article/CJFDTOTAL-ZNGD202012024.htmYu Qianmi, Tai Bowen, Niu Jiqiang, et al. Effect of unevenly distributed fine-grained soil in space on moisture migration[J]. Journal of Central South University: Science and Technology, 2020, 51(12): 3503-3514. https://www.cnki.com.cn/Article/CJFDTOTAL-ZNGD202012024.htm [4] 杨志浩, 岳祖润, 冯怀平. 非饱和粉土路基内水分迁移规律试验研究[J]. 岩土力学, 2020, 41(7): 2241-2251. https://www.cnki.com.cn/Article/CJFDTOTAL-YTLX202007011.htmYang Zhihao, Yue Zurun, Feng Huaiping. Experimental study on moisture migration properties in unsaturated silty subgrade[J]. Rock and Soil Mechanics, 2020, 41(7): 2241-2251. https://www.cnki.com.cn/Article/CJFDTOTAL-YTLX202007011.htm [5] 肖泽岸, 朱霖泽, 侯振荣, 等. 水盐相变对硫酸盐渍土基质吸力影响规律研究[J]. 岩土工程学报, 2022, 44(10): 1935-1941. https://www.cnki.com.cn/Article/CJFDTOTAL-YTGC202210020.htmXiao Zean, Zhu Linze, Hou Zhenrong, et al. Effects of water/salt phase transition on matric suction of sulfate saline soil[J]. Chinese Journal of Geotechnical Engineering, 2022, 44(10): 1935-1941. https://www.cnki.com.cn/Article/CJFDTOTAL-YTGC202210020.htm [6] 郭剑峰, 陈正汉, 郭楠. 延安新区高填方工程的变形与水分迁移耦合分析[J]. 岩土工程学报, 2021, 43(S1): 143-148. https://www.cnki.com.cn/Article/CJFDTOTAL-YTGC2021S1028.htmGuo Jianfeng, Chen Zhenghan, Guo Nan. Application of incremental nonlinear consolidation theory for unsaturated soil in high fill projects[J]. Chinese Journal of Geotechnical Engineering, 2021, 43(S1): 143-148. https://www.cnki.com.cn/Article/CJFDTOTAL-YTGC2021S1028.htm [7] Bruce R R, Klute A. The measurement of soil moisture diffusivity[J]. Soil Science Society of America Journal, 1956, 20(4): 458-462. [8] Turner N C, Parlange J Y. Two-dimensional similarity solution: theory and application to the determination of soil-water diffusivity[J]. Soil Science Society of America Journal, 1975, 39(3): 387-390. [9] Clothier B E, White I. Measurement of sorptivity and soil water diffusivity in the field[J]. Soil Science Society of America Journal, 1981, 45(2): 241-245. [10] van Grinsven J J M, Dirksen C, Bouten W. Evaluation of the hot air method for measuring soil water diffusivity[J]. Soil Science Society of America Journal, 1985, 49(5): 1093-1099. [11] Cassel D K, Warrick A W, Nielsen D R, et al. Soil-water diffusivity values based upon time dependent soil-water content distributions[J]. Soil Science Society of America Journal, 1968, 32(6): 774-777. [12] Warrick A W. Soil water diffusivity estimates from one-dimensional absorption experiments[J]. Soil Science Society of America Journal, 1994, 58(1): 72-77. [13] Valiantzas J D, Londra P, Sassalou A. Explicit formulae for soil water diffusivity using the one-step outflow technique[J]. Soil Science Society of America Journal, 2007, 71(6): 1685-1693. [14] Londra P A, Valiantzas J D. Soil water diffusivity determination using a new two-point outflow method[J]. Soil Science Society of America Journal, 2011, 75(4): 1343-1346. [15] 马丽娜, 严松宏, 王起才, 等. 客运专线无碴轨道泥岩地基原位浸水膨胀变形试验[J]. 岩石力学与工程学报, 2015, 34(8): 1684-1691. https://www.cnki.com.cn/Article/CJFDTOTAL-YSLX201508021.htmMa Lina, Yan Songhong, Wang Qicai, et al. In-situ tests on swelling deformation of mudstone foundation upon soaking under ballastless track of passenger railway line[J]. Chinese Journal of Rock Mechanics and Engineering, 2015, 34(8): 1684-1691. https://www.cnki.com.cn/Article/CJFDTOTAL-YSLX201508021.htm [16] Li X, Zhang L M, Fredlund D G. Wetting front advancing column test for measuring unsaturated hydraulic conductivity[J]. Canadian Geotechnical Journal, 2009, 46(12): 1431-1445. [17] Zhang F, Zhang X L, Li Y J, et al. Quantitative description theory of water migration in rock sites based on infrared radiation temperature[J]. Engineering Geology, 2018, 241: 64-75. [18] Wang Z, Lu J H, Wu L S, et al. Visualizing preferential flow paths using ammonium carbonate and a pH indicator[J]. Soil Science Society of America Journal, 2002, 66(2): 347-351. [19] Espejo A, Giráldez J V, Vanderlinden K, et al. A method for estimating soil water diffusivity from moisture profiles and its application across an experimental catchment[J]. Journal of Hydrology, 2014, 516: 161-168. [20] Zhang M Z, Ye G, van Breugel K. Microstructure-based modeling of water diffusivity in cement paste[J]. Construction and Building Materials, 2011, 25(4): 2046-2052. [21] Khalilin, Russellar, Khoshghalba. Unsaturated-soils: research and applications[M]. UK, London: CRC Press, 2014: 1155-1161. [22] 李杰林, 刘汉文. 冻融循环作用下砂岩孔隙体积变形模型的建立与分析[J]. 冰川冻土, 2018, 40(6): 1173-1180. https://www.cnki.com.cn/Article/CJFDTOTAL-BCDT201806011.htmLi Jielin, Liu Hanwen. Establishment and analysis of the volumetric deformation model of sandstone pores under the effect of freezing-thawing cycles[J]. Journal of Glaciology and Geocryology, 2018, 40(6): 1173-1180. https://www.cnki.com.cn/Article/CJFDTOTAL-BCDT201806011.htm [23] 李海波, 朱巨义, 郭和坤. 核磁共振T2谱换算孔隙半径分布方法研究[J]. 波谱学杂志, 2008, 25(2): 273-280. https://www.cnki.com.cn/Article/CJFDTOTAL-PPXZ200802017.htmLi Haibo, Zhu Juyi, Guo Hekun. Methods for calculating pore radius distribution in rock from NMR T2 spectra[J]. Chinese Journal of Magnetic Resonance, 2008, 25(2): 273-280. https://www.cnki.com.cn/Article/CJFDTOTAL-PPXZ200802017.htm [24] Dlubac K, Knight R, Song Y Q, et al. Use of NMR logging to obtain estimates of hydraulic conductivity in the High Plains aquifer, Nebraska, USA[J]. Water Resources Research, 2013, 49(4): 1871-1886. [25] Carpenter T A, Davies E S, Hall C, et al. Capillary water migration in rock: process and material properties examined by NMR imaging[J]. Materials and Structures, 1993, 26(5): 286-292. -
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