Rock and Soil Mechanics ›› 2020, Vol. 41 ›› Issue (4): 1195-1202.doi: 10.16285/j.rsm.2019.5785

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Evolution law of pore-size distribution in soil-water retention test

NIU Geng1, SHAO Long-tan1, SUN De-an2, 3, WEI Chang-fu3, GUO Xiao-xia1, XU Hua4   

  1. 1. State Key Laboratory of Structural Analysis of Industrial Equipment, Department of Engineering Mechanics, Dalian University of Technology, Dalian, Liaoning 116085, China 2. Department of Civil Engineering, Shanghai University, Shanghai 200444, China 3 Guangxi Key Laboratory of Geomechanics and Geotechnical Engineering, Guilin University of Technology, Guilin, Guangxi 541004, China 4. Shandong Province Administration of Haihe River Basin, Jinan, Shandong 250100, China
  • Online:2020-04-27 Published:2020-09-27
  • About author:NIU Geng, male, born in 1991, PhD candidate, majoring in unsaturated soil mechanics
  • Supported by:
    This work was supported by the National Natural Science Foundation of China (51479023, 11372078).

Abstract: This paper is to measure the soil-water retention curves (SWRC) of undisturbed and compacted soil specimens and compare the differences in measured data between these two soils. The mercury intrusion porosimetry (MIP) tests are conducted to explore the difference in the pore size distributions (PSD) between the undisturbed and compacted specimens and investigate the evolution law of PSD during drying. By considering shrinkage during drying, the basic parameters of SWRC can be determined based on the PSD. The results show that the undisturbed specimens in the wide suction range exhibit a unimodal PSD. The saturated compacted-specimen exhibits a unimodal PSD, but becomes the bimodal structure obviously during further drying. The SWRC of undisturbed specimens has a typical shape of “S”, but the compacted specimens have a “horizontal stage” in the transition zone. The pore diameters governing the air entry value and residual value can be determined by the PSD of MIP tests, and then corresponding suctions can be calculated, which are consistent with the physical meaning.

Key words: soil water retention curve, pore-size distribution, mercury intrusion porosimetry, air entry value, residual value