岩土工程
保水曲线
土壤水分
土壤科学
环境科学
粒度分布
Pedotransfer函数
毛细管作用
地质学
土壤级配
保水性
材料科学
导水率
复合材料
粒径
古生物学
作者
Shengmin Luo,Baochun Zhou,William J. Likos,Ning Lu
出处
期刊:Journal of Geotechnical and Geoenvironmental Engineering
[American Society of Civil Engineers]
日期:2024-02-01
卷期号:150 (2)
标识
DOI:10.1061/jggefk.gteng-11647
摘要
Pore-size distribution (PSD) of soil is a fundamental property that determines flows of water, heat, chemicals, and electricity and controls distributions of stress and deformation. PSD can be intrinsically related to the soil–water retention curve (SWRC), which is a constitutive relationship describing how the soil skeleton retains pore water via adsorption and capillarity. A general framework to quantify soil's PSD is proposed by first fitting an analytical SWRC model to experimental water retention curves that explicitly separate the SWRC into an adsorptive SWRC and a capillary SWRC. The PSD is then estimated at incremental steps by combining the capillary SWRC and the conventional Young–Laplace equation relating capillary pressure to pore size. Cumulative and density PSD curves for 11 soils covering a wide spectrum of soil types are determined and compared with the PSD functions independently measured using mercury intrusion porosimetry (MIP). Good agreement is observed in the estimated pore size range, distribution pattern, and peak position determined from the two different methods. Differences observed in the methods are attributed to differences inherent in the use of wetting and nonwetting fluids to probe the pore space. The SWRC-based method generally characterizes pore sizes ranging from 100 to 0.02 μm with a major peak located within a pore diameter range of 1–10 μm. As the clay content increases, a secondary peak becomes evident at smaller pore sizes (about 0.01–0.1 μm), where the bimodal pattern reflects the dual-porosity microstructure commonly observed for clayey soils. For soils containing swelling clays, PSD can change substantially with variation in water content; thus, the water-based method is more appropriate than MIP for applications to geotechnical engineering practice.
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