A new and simple stress-dependent water retention model for unsaturated soil

C. Zhou, Charles Wang Wai Ng

Research output: Journal article publicationJournal articleAcademic researchpeer-review

60 Citations (Scopus)


The water retention curve (WRC) is an important hydraulic property of unsaturated soil needed for seepage analysis. Experimental evidence shows that the WRC is affected by various factors such as net stress and soil type. Many attempts have been made to describe the effects of net stress by including the void ratio in a water retention model. But the void ratio (i.e., soil density) is not the only parameter altered by the application of net stress. The pore structure, including the pore size distribution, pore shape and pore orientation, is also changed. Thus the influence of net stress on the WRC should not be treated as equivalent to density effects. In this study, it is verified that the inclusion of the void ratio cannot adequately capture the effects of net stress on the water retention behaviour. A new and simple water retention model is thus developed by considering the stress effects on the void ratio as well as the pore structure. The model is then applied to simulate the WRCs of three different soils tested over a wide range of stress conditions, including isotropic and anisotropic stress conditions. The results show that better predictions of experimental data can be made by incorporating the effects of net stress on both the void ratio and the pore structure.

Original languageEnglish
Pages (from-to)216-222
Number of pages7
JournalComputers and Geotechnics
Publication statusPublished - Oct 2014
Externally publishedYes


  • Constitutive relation
  • Suction
  • Unsaturated soil
  • Water retention curve

ASJC Scopus subject areas

  • Geotechnical Engineering and Engineering Geology
  • Computer Science Applications


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