Microscopic Pore Structure Characteristics and Hydraulic Tortuosity of Unsaturated Remodeled Weakly Expansive Soil

LIN Wen-bo; NING Gui-xia; MA Li-na; DING Xiao-gang; ZHANG Yang; LUO Wei

doi:10.11988/ckyyb.20221440

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Journal of Changjiang River Scientific Research Institute ›› 2024, Vol. 41 ›› Issue (4) : 124-130. DOI: 10.11988/ckyyb.20221440

Rock-Soil Engineering

Microscopic Pore Structure Characteristics and Hydraulic Tortuosity of Unsaturated Remodeled Weakly Expansive Soil

LIN Wen-bo¹, NING Gui-xia^1,2, MA Li-na^1,2, DING Xiao-gang¹, ZHANG Yang¹, LUO Wei¹

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Abstract

To investigate the variation in pore distribution of remodeled weakly expansive soil at different dry densities, specimens with dry densities of 1.40, 1.50, 1.60, 1.70, 1.80 g/cm³ were prepared using a press sample machine. The pore structure and distribution characteristics of these specimens were analyzed through mercury-injection and saturation-permeability tests. The hydraulic tortuosity of the specimens were calculated based on mercury piezometric and saturation permeability tests. The results indicate a consistent pattern in the process of mercury entering and exiting specimens of varying dry densities. Due to distinct entry and exit paths and the presence of bottleneck pores, the mercury retains within the specimens. Furthermore, an increase in dry density results in a reduction in both pore volume and the quantity of large pores. The soil's pore structure becomes more intricate with higher dry densities, exhibiting a negative correlation between average pore diameter, porosity, total pore volume, and fractal dimension. Based on the experimental outcomes, saturated permeability coefficients and hydraulic tortuosity at varied dry densities were computed, revealing that the increase in hydraulic tortuosity with higher dry density lies in the changes in pore size and structure, consequently affecting the fluid's permeation ability within the soil.

Key words

expansive soil / mercury piezometric method / microstructure / saturated permeability coefficient / hydraulic tortuosity

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LIN Wen-bo, NING Gui-xia, MA Li-na, DING Xiao-gang, ZHANG Yang, LUO Wei. Microscopic Pore Structure Characteristics and Hydraulic Tortuosity of Unsaturated Remodeled Weakly Expansive Soil[J]. Journal of Changjiang River Scientific Research Institute. 2024, 41(4): 124-130 https://doi.org/10.11988/ckyyb.20221440

References

[1] 马丽娜. 高速铁路路基低黏土矿物泥岩膨胀机理及影响研究[D]. 兰州: 兰州交通大学, 2016: 12-37.(MA Li-na. Research on Low Clay Mineral Mudstone Expansion Mechanism and Influence for High-speed Railway Subgrade[D].Lanzhou: Lanzhou Jiaotong University, 2016: 12-37.(in Chinese))
[2] 李向全. 粘性土微结构定量模型及其工程地质特征研究[M]. 北京: 地质出版社, 1995: 3-13. (LI Xiang-quan. Quantitative Microstructure Models of Clayey Soils and Their Engineering Behaviors[M]. Beijing: Geological Publishing House, 1995: 3-13.(in Chinese))
[3] 张唐瑜,马丽娜,张戎令,等.基于MIP的压实作用对“微膨胀性” 重塑泥岩微观结构影响分析[J].工程地质学报,2019,27(4):717-722.(ZHANG Tang-yu,MA Li-na,ZHANG Rong-ling,et al. Analysis for Effect of MIP-based Compaction on Micro-structure of Remodeled Mud Stone with “Micro-expansion”[J]. Journal of Engineering Geology,2019,27(4):717-722.(in Chinese))
[4] 马丽娜,李佳敏,王起才,等.上覆荷载影响下膨胀土微观机理孔隙特征[J].兰州大学学报(自然科学版),2021,57(3):318-322.(MA Li-na,LI Jia-min,WANG Qi-cai,et al.Study on the Pore Characteristics of the Micro Mechanism of Expansive Soil under the Influence of Overlying Load[J]. Journal of Lanzhou University (Natural Sciences),2021,57(3):318-322.(in Chinese))
[5] 冯怀平, 马德良, 刘启塬, 等. 基于扫描电镜图像的土体三维视孔隙率定量计算方法[J]. 岩土工程学报, 2019, 41(3): 574-580. (FENG Huai-ping, MA De-liang, LIU Qi-yuan, et al. Method for Calculating Three Dimensional Apparent Porosity of Soils Based on SEM Images[J]. Chinese Journal of Geotechnical Engineering, 2019, 41(3): 574-580.(in Chinese))
[6] ROMERO E,GENS A,LLORET A.Water Permeability, Water Retention and Microstructure of Unsaturated Compacted Boom Clay[J]. Engineering Geology,1999,54(1/2):117-127.
[7] SIMMS P H,YANFUL E K. Predicting Soil-Water Characteristic Curves of Compacted Plastic Soils from Measured Pore-size Distributions[J]. Géotechnique,2002,52(4): 269-278.
[8] SIMMS P H, YANFUL E K. Measurement and Estimation of Pore Shrinkage and Pore Distribution in a Clayey till during Soil-Water Characteristic Curve Tests[J]. Canadian Geotechnical Journal, 2001, 38(4): 741-754.
[9] 邵帅, 邵生俊, 朱丹丹, 等. 黄土的细观结构演变与宏观结构性变化规律[J]. 岩土工程学报, 2021, 43(增刊1): 64-70. (SHAO Shuai, SHAO Sheng-jun, ZHU Dan-dan, et al. Microstructure Evolution and Macro-structural Change Law of Loess[J]. Chinese Journal of Geotechnical Engineering, 2021, 43(Supp.1): 64-70.(in Chinese))
[10] 蒋明镜,李志远,黄贺鹏,等.南海软土微观结构与力学特性试验研究[J].岩土工程学报,2017,39(增刊2):17-20.(JIANG Ming-jing,LI Zhi-yuan,HUANG He-peng,et al. Experimental Study on Microstructure and Mechanical Properties of Soft Soil in South China Sea[J]. Chinese Journal of Geotechnical Engineering,2017,39(Supp.2):17-20.(in Chinese))
[11] 江强强, 刘路路, 焦玉勇, 等. 干湿循环下滑带土强度特性与微观结构试验研究[J]. 岩土力学, 2019, 40(3): 1005-1012, 1022. (JIANG Qiang-qiang, LIU Lu-lu, JIAO Yu-yong, et al. Strength Properties and Microstructure Characteristics of Slip Zone Soil Subjected to Wetting-drying Cycles[J]. Rock and Soil Mechanics, 2019, 40(3): 1005-1012, 1022.(in Chinese))
[12] GHANBARIAN B, HUNT A G, EWING R P,et al. Tortuosity in Porous Media: A Critical Review[J]. Soil Science Society of America Journal, 2013, 77(5): 1461.
[13] COMITI J, RENAUD M. A New Model for Determining Mean Structure Parameters of Fixed Beds from Pressure Drop Measurements: Application to Beds Packed with Parallelepipedal Particles[J]. Chemical Engineering Science, 1989, 44(7): 1539-1545.
[14] YU B M, LI J H. A Geometry Model for Tortuosity of Flow Path in Porous Media[J]. Chinese Physics Letters, 2004, 21(8): 1569-1571.
[15] 张平,房营光,闫小庆,等.不同干燥方法对重塑膨润土压汞试验用土样的影响试验研究[J].岩土力学,2011,32(增刊1):388-391.(ZHANG Ping,FANG Ying-guang,YAN Xiao-qing,et al. Experimental Study on the Influence of Different Drying Methods on Soil Samples for Mercury Intrusion Test of Remolded Bentonite[J]. Rock and Soil Mechanics,2011,32(Supp.1):388-391.(in Chinese))
[16] 王升福,杨平, 刘贯荣, 等. 人工冻融软黏土微观孔隙变化及分形特性分析[J]. 岩土工程学报, 2016, 38(7): 1254-1261. (WANG Sheng-fu, YANG Ping, LIU Guan-rong, et al. Micro Pore Change and Fractal Characteristics of Artificial Freeze Thaw Soft Clay[J]. Chinese Journal of Geotechnical Engineering, 2016, 38(7): 1254-1261.(in Chinese))
[17] 李文采,田寒友,白京,等.采用压汞法研究不同冷冻羊肉冰晶结构特征[J].农业工程学报,2019,35(20):280-287.(LI Wen-cai,TIAN Han-you,BAI Jing,et al. Investigation of Ice Crystal Structure Characteristics of Different Frozen Lamb by Using Mercury Intrusion[J]. Transactions of the Chinese Society of Agricultural Engineering,2019,35(20):280-287.(in Chinese))
[18] SASANIAN S, NEWSON T A. Use of Mercury Intrusion Porosimetry for Microstructural Investigation of Reconstituted Clays at High Water Contents[J]. Engineering Geology, 2013, 158: 15-22.
[19] 王明磊,张雁,殷潇潇.基于Menger海绵模型的煤矸石粉改良膨胀土微结构特征[J].农业工程学报,2020,36(23):124-130.(WANG Ming-lei,ZHANG Yan,YIN Xiao-xiao.Microstructure Characteristics of Expansive Soil with Coal Gangue Based on Menger Sponge Model[J]. Transactions of the Chinese Society of Agricultural Engineering,2020,36(23):124-130.(in Chinese))
[20] 陶高梁,朱学良,胡其志,等.黏性土压缩过程临界孔径现象及固有分形特征[J].岩土力学,2019,40(1):81-90.(TAO Gao-liang,ZHU Xue-liang,HU Qi-zhi,et al.Critical Pore-size Phenomenon and Intrinsic Fractal Characteristic of Clay in Process of Compression[J]. Rock and Soil Mechanics,2019,40(1):81-90.(in Chinese))
[21] SUTERA S P,SKALAK R.The History of Poiseuille's Law[J].Annual Review of Fluid Mechanics,1993,25:1-19.
[22] 孔祥言. 高等渗流力学[M]. 合肥: 中国科学技术大学出版社, 1999. (KONG Xiang-yan. Advanced Mechanics of Fluids in Porous Media[M]. Hefei: University of Science and Technology of China Press, 1999.(in Chinese))