作者中心
专家审稿
编委审稿
主编审稿
EXPERIMENTAL STUDY ON CHARACTERISTICS OF PORE WATER DISTRIBUTION AND WATER-HOLDING CAPACITY OF SOIL
-
摘要: 采用轴平移技术对砂土、粉质黏土、黏土3种土质的土-水特征曲线进行了测试分析，并结合核磁共振技术测得了试样在不同基质吸力加载步条件下的T2时间（横向弛豫时间）分布曲线，从细微观角度分析了脱湿过程中孔隙水在土体中赋存分布的情况。实验结果表明：3种土质的体积含水率随着控制吸力的增大而减少，该脱湿曲线可分为边界效应区、过渡区与残余区3个区域。其中，黏土的持水特性明显大于粉质黏土和砂土。核磁共振的试验结果与压力板仪获得的脱湿过程是对应的，从微细观角度展示了土体的排水过程。在排水过程中，总体上具有较大势能的大孔隙水先排出，随后小孔隙开始排水，但这一规律并不绝对，由于土体孔隙结构的复杂性，会出现大小孔隙同时排水以及土样中水分重分布的现象。Abstract: The soil water characteristic curves of sand, silty clay and clay are measured by axis translation technique. The T2 distribution curve of specimens are tested under different matric suction loading steps combining with nuclear magnetic resonance(NMR) technique. The distribution of pore water in soil is discussed with the T2 distribution curve from the microscopic point of view during drying process. The results show that volumetric water content gradually reduces with the increase of the suction. The drying curve can be divided into three sections:boundary effect zone, transition zone and residual zone. In addition, the clay water-holding capacity is obviously higher than that of silt and sand. The tests of NMR are corresponded with drying process in the pressure plate apparatus. The results of NMR tests further show the drainage process of soil from the microscopic of perspective. On the whole, the large pore water with large potential energy is discharged first in the drainage process of soil, and then the water in small pores begins to drain. However, this rule is not absolute, because of the complexity of the soil pore structure. There will be a phenomenon of simultaneous discharge of different size porosity of pore water and the redistribution of pore water in soil occurred during the drying process.
-
Key words:
- Soil-water characteristic curve /
- Unsaturated soil /
- NMR /
- Pore-water distribution /
- T2 distribution
-
图 3 砂土、粉质黏土与黏土的粒径级配曲线
Figure 3. Grain size distribution curves of sand，silty clay and clay
图 5 不同土质类在0～20kPa吸力下的T2分布曲线
Figure 5. T2 distribution curves of different soils for 0～20kPa suction
图 9 不同土质在0～1200kPa吸力下的T2分布曲线
Figure 9. T2 distribution curves of different soils for 0～1200kPa suction
表 1 土的基本物性指标
Table 1. Physical properties of soils
土质 风干含水率
/%比重 液限
/%塑限
/%塑性
指数黏土 4.60 2.72 34.2 23.5 10.7 粉质黏土 1.70 2.71 23.2 13.1 10.1 砂土 0.80 2.68 / / / 
下载: 导出CSV
表 2 V-G模型参数表
Table 2. Parameters of V-G model
土质 α n m θr/% θs/% R2 黏土 0.01 2.45 0.59 26.90 47.60 0.96 粉质黏土 0.07 1.81 0.45 20.10 41.31 0.96 砂土 0.08 1.94 0.49 2.40 40.68 0.97
下载: 导出CSV
-
Bird N R A,Preston A R,Randall E W,et al. 2005. Measurement of the size distribution of water-filled pores at different matric potentials by stray field nuclear magnetic resonance[J]. European Journal of Soil Science,56 (1):135~143. doi: 10.1111/ejs.2005.56.issue-1 Cadoret T,Mavko G,Zinszner B. 1998. Fluid distribution effect on sonic attenuation in partially saturated limestones[J]. Geophysics,63 (1):154~160. doi: 10.1190/1.1444308 Chen B,Zhu R,Chang F Z. 2011. Microstructural characteristics of volumetric deformation of clay under different compression stresses[J]. Rock and Soil Mechanics,32 (S1):95~99,369. https://www.researchgate.net/publication/286721038_Microstructural_characteristics_of_volumetric_deformation_of_clay_under_different_compression_stresses Chen P,Wei C F,Liu J,et al. 2013. Strength Theory Model of Unsaturated Soils with Suction Stress Concept[J]. Journal of Applied Mathematics,8:245~262. https://www.researchgate.net/publication/288307880_Strength_Theory_Model_of_Unsaturated_Soils_with_Suction_Stress_Concept Chen P,Wei H Z,Li H,et al. 2010. Effect of capillary hysteresis on two-phase flow in porous media[J]. Chinese Journal of Rock Mechanics and Engineering,29 (10):2148~2158. https://www.researchgate.net/publication/286178128_Effect_of_capillary_hysteresis_on_two-phase_flow_in_porous_media Coates G,Xiao L Z,Prammer M,et al. 2007. NMR logging principles and applications[M]. Beijing:Petroleum Industry Press. Dong Q,Hou L,Zhao B Y. 2012. Influence of matric suction on shear strength of unsaturated silty sand[J]. Journal of Central South University(Science and Technology),43 (10):4017~4021. https://www.researchgate.net/publication/272057051_Influence_of_Matric_Suction_on_Shear_Strength_Behavior_of_Unsaturated_Silty_Sand Li K L. 2012. Microstructure of silica Fume-Metakaolin based Geopolymer[J]. Journal of Building Materials,15 (4):553~556. https://www.researchgate.net/publication/290267698_Microstructure_of_silica_fume-metakaolin_based_geopolymer Li Z Q,Li T,Hu R L,et al. 2007. Methods for testing and predicting of SWCC in unsaturated soil mechanics[J]. Journal of Engineering Geology,15 (5):700~707. http://www.sciencedirect.com/science/article/pii/S0013795209002452 Lin H Z,Yu Y Z,Li G X,et al. 2009. On application of Soil-Water characteristic curves to landslide forecast[J]. Chinese Journal of Rock Mechanics and Engineering,28 (12):2569~2576. https://www.researchgate.net/publication/290628802_On_application_of_soil-water_characteristic_curves_to_landslide_forecast Lu N,Likos W J,Wei C F,et al. 2012. Unsaturated Soil Mechanics[M]. Beijing:China Higher Education Press:127~136. Shi B,Jiang H T. 2001. Research on the analysis techniques for clayey soil microstructure[J]. Chinese Journal of Rock Mechanics and Engineering,20 (6):864~870. https://www.researchgate.net/publication/287434470_Research_on_the_analysis_techniques_for_clayey_soil_microstructure Tan L,Wei C F,Tian H H,et al. 2015. Experimental study of unfrozen water content of frozen soils by low-field nuclear magnetic resonance[J]. Rock and Soil Mechanic,36 (6):1566~1572. https://www.researchgate.net/publication/282682156_Experimental_study_of_unfrozen_water_content_of_frozen_soils_by_low-field_nuclear_magnetic_resonance Tao G L. 2010. Fractal approach on pore structure of rock and soil porous media and its applications[D]. Wuhan:Wuhan University of Technology. Tian H H,Wei C F,Wei H Z,et al. 2014. A NMR-based analysis of drying processes of compacted clayey sands[J]. Rock and Soil Mechanic,35 (8):2129~2136. https://www.researchgate.net/publication/289634909_A_NMR-based_analysis_of_drying_processes_of_compacted_clayey_sands Tian H H,Wei H Z,Yan R T,et al. 2011. Application of low-field NMR to the studies of the THF hydrate formation process[J]. Natural Gas Industry,31 (7):97~100. https://www.researchgate.net/publication/286973702_Application_of_low-field_NMR_to_the_studies_of_the_THF_hydrate_formation_process Van Genuchten M T. 1980. A closed-form equation for predicting the hydraulic conductivity of unsaturated soils[J]. Soil Science Society of America Journal,44 (5):892~895. doi: 10.2136/sssaj1980.03615995004400050002x Wang H Z,Zhang X L,Wu J. 2008. Test guide for magnetic resonance imaging[M]. Beijing:Science Press:3~10. White N F,Duke H R,Sunada D K,et al. 1970. Physics of desaturation in porous materials[J]. Journal of Irrigation and Drainage Division,96:165~191. Zhang X D. 2010. Research on the principle problem relating to soil-water characteristic curve and its application in unsaturated soil mechanics[D]. Beijing:Beijing Jiaotong University. 陈宝,朱嵘,常防震. 2011. 不同压应力作用下黏土体积变形的微观特征[J]. 岩土力学,32 (增刊):95~99,369. http://www.cnki.com.cn/Article/CJFDTOTAL-YTLX2011S1018.htm 陈盼,魏厚振,李幻,等. 2010. 多孔介质中两相流动过程的毛细滞回效应[J]. 岩石力学与工程学报,29 (10):2148~2158. http://www.cnki.com.cn/Article/CJFDTOTAL-YSLX201010028.htm Coates G,肖立志,Prammer M,等. 2007. 核磁共振测井原理与应用[M]. 北京:石油工业出版社. 董倩,侯龙,赵宝云. 2012. 基质吸力对非饱和粉质砂土抗剪强度的影响[J]. 中南大学学报(自然科学版),43 (10):4017~4021. http://www.cnki.com.cn/Article/CJFDTOTAL-ZNGD201210041.htm 李克亮. 2012. 硅粉-偏高岭土基地聚合物微观结构分析[J]. 建筑材料学报,15 (4):553~556. http://www.cnki.com.cn/Article/CJFDTOTAL-JZCX201204025.htm 李志清,李涛,胡瑞林,等. 2007. 非饱和土土水特征曲线(SWCC)测试与预测[J]. 工程地质学报,15 (5):700~707. http://www.gcdz.org/CN/abstract/abstract8925.shtml 林鸿州,于玉贞,李广信,等. 2009. 土水特征曲线在滑坡预测中的应用性探讨[J]. 岩石力学与工程学报,28 (12):2569~2576. http://www.cnki.com.cn/Article/CJFDTOTAL-YSLX200912030.htm Lu N,Likos W J,韦昌富,等. 2012. 非饱和土力学[M]. 北京:高等教育出版社:127~136. 施斌,姜洪涛. 2001. 黏性土的微观结构分析技术研究[J]. 岩石力学与工程学报,20 (6):864~870. http://www.cnki.com.cn/Article/CJFDTOTAL-YSLX200106030.htm 谭龙,韦昌富,田慧会,等. 2015. 冻土未冻水含量的低场核磁共振试验研究[J]. 岩土力学,36 (6):1566~1572. http://www.cnki.com.cn/Article/CJFDTOTAL-YTLX201506006.htm 陶高梁. 2010. 岩土多孔介质孔隙结构的分形研究及其应用[D]. 武汉:武汉理工大学. 田慧会,韦昌富,魏厚振,等. 2014. 压实黏质砂土脱湿过程影响机制的核磁共振分析[J]. 岩土力学,35 (8):2129~2136. http://www.cnki.com.cn/Article/CJFDTOTAL-YTLX201408001.htm 田慧会,魏厚振,颜荣涛,等. 2011. 低场核磁共振在研究四氢呋喃水合物形成过程中的应用[J]. 天然气工业,31 (7):97~100. http://www.cnki.com.cn/Article/CJFDTOTAL-TRQG201107030.htm 汪红志,张学龙,武杰. 2008. 核磁共振成像技术试验教程[M]. 北京:科学出版社:3~10. 张雪东. 2010. 土水特征曲线及其在非饱和土力学中应用的基本问题研究[D]. 北京:北京交通大学 -
点击查看大图
图(9) / 表(2)
计量
- 文章访问数: 3543
- HTML全文浏览量: 470
- PDF下载量: 634
- 被引次数: 0
