Hydraulic conductivity over a wide suction range of loess with different dry densities  

作　　者：Xiaokun Hou Shengwen Qi Yan Li Fangcui Liu Tonglu Li Hua Li 

机构地区：[1]State Key Laboratory of Lithospheric and Environmental Coevolution,Institute of Geology and Geophysics,Chinese Academy of Sciences,Beijing,100029,China [2]University of Chinese Academy of Sciences,Beijing,100049,China [3]Innovation Academy for Earth Science,Beijing,100029,China [4]School of Civil Engineering,University of A Coruña,A Coruña,15071,Spain [5]Department of Geological Engineering,Chang’an University,Xi’an,710054,China [6]School of Civil Engineering and Architecture,Xi’an Jiaotong University of City College,Xi’an,710018,China

出　　处：《Journal of Rock Mechanics and Geotechnical Engineering》2025年第1期481-492,共12页岩石力学与岩土工程学报(英文)

基　　金：supported by the National Natural Science Foundation of China(Grant No.41825018);Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDA23090402);the National Natural Science Foundation of China(Grant No.42141009).

摘　　要：Experimental research into the hydraulic conductivity curve (HCC) of unsaturated soil is limited due to the inherent challenge associated with labor, cost, and time. Typically, the HCC is estimated using the soil water characteristic curve (SWCC) based models and saturated hydraulic conductivity (SHC). However, the efficiency of the SWCC-based model is rarely assessed, and the influence of soil density and pore structure on HCC remains incomplete due to limited experimental data. To address this gap, this study employs an innovative filter-paper-based column method, which can measure the HCC over a wide suction range (e.g. 0−105 kPa), to capture the HCCs of both intact and compacted specimens with varying dry densities. The efficiency of two typical SWCC-based models is assessed using the measured data. Meanwhile, the mercury intrusion porosity (MIP) technique is employed to obtain the pore characteristic (i.e. pore size distribution (PSD)) and a method of predicting the HCC using the PSD data is proposed, emphasizing the dominant role of the pore structure in shaping the HCC. The results reveal that the dry density's influence on the HCC is primarily observed within the low suction range, corresponding to variations in the dominant and large pores. In the high suction range, the HCCs align along a linear trajectory when plotted in a log-log format. A notable finding is the overestimation of the HCC obtained from the SWCC-based models using the measured SHC. When the SHC is regarded as a fitting parameter, good agreement is achieved. The adjusted SHC value is typically 0-1 order of magnitude lower than the measured value, and this discrepancy diminishes as dry density increases. On the other hand, the proposed PSD-based model performs well with the measured SHC data. Caution is exercised when using the SHC to estimate the HCC for modeling water movement in partially saturated soil.

关 键 词：Hydraulic conductivity curve Wide suction range Dry density Pore size distribution Saturated hydraulic conductivity 

分 类 号：TV223[水利工程—水工结构工程]