Effective Stress and Effective Stress Equation

  • Longtan ShaoEmail author
  • Xiaoxia Guo
  • Tiande Wen
  • Boya Zhao
Conference paper


The concept of effective stress and the effective stress equation is fundamental for establishing the theory of strength and the relationship of stress and strain in soil mechanics. However, up till now, the physical meaning of effective stress has not been explained clearly, and the theoretical basis of the effective stress equation has not been proposed. Researchers have not yet reached a common understanding of the feasibility of the concept of effective stress and effective stress equation for unsaturated soils. Focusing on these problems, new viewpoints for explicitly elucidating the effective stress and deriving the effective stress equation are given in this paper, including that the effective stress should be defined as the soil skeleton stress due to all the external forces excluding pore fluid pressure, and that the soil skeleton should include a fraction of pore water which can bears and passes the load together with soil particles. The relationship between the effective stress and the shear strength and the deformation of unsaturated soils is preliminarily verified by experiments and quoting test data from literature.


Effective stress Effective stress equation Unsaturated soils Soil skeleton stress Pore fluid pressure 


  1. 1.
    Aqtash, U., Bandini, P.: Prediction of unsaturated shear strength of an adobe soil from the soil–water characteristic curve. Constr. Build. Mater. 98, 892–899 (2015)CrossRefGoogle Scholar
  2. 2.
    Cunningham, M.R., Ridley, A.M., Dineen, K., et al.: The mechanical behaviour of a reconstituted unsaturated silty clay. Geotechnique 53(2), 183–194 (2003)CrossRefGoogle Scholar
  3. 3.
    Escario, V., Juca, J.F.T., Coppe, M.S.: Strength and deformation of partly saturated soils. In: Proceedings of 12th ICSMFE, Rio de Janeiro, Brazil, vol. 11, pp. 43–46 (1989)Google Scholar
  4. 4.
    Herle, I., Gudehus, G.: Determination of parameters of a hypoplastic constitutive model from properties of grain assemblies. Mech. Cohesive-Frict. Mater. 4(5), 461–486 (1999)CrossRefGoogle Scholar
  5. 5.
    Khalili, N., Geiser, F., Blight, G.E.: Effective stress in unsaturated soils: review with new evidence. Int. J. Geomech. 4, 115–126 (2004)CrossRefGoogle Scholar
  6. 6.
    Kayadelen, C., Tekinsoy, M.A., Taskiran, T.: Influence of matric suction on shear behavior of a residual clayey soil. Environ. Geol. 53, 891–901 (2007)CrossRefGoogle Scholar
  7. 7.
    Lee, I.M., Sung, S.G., Cho, G.C.: Effect of stress state on the unsaturated shear strength of a weathered granite. Can. Geotech. J. 42(2), 624–631 (2005)CrossRefGoogle Scholar
  8. 8.
    Miao, L., Houston, S.L., Cui, Y., et al.: Relationship between soil structure and mechanical behavior for an expansive unsaturated clay. Can. Geotech. J. 44(2), 126–137 (2007)CrossRefGoogle Scholar
  9. 9.
    Miao, L., Liu, S., Lai, Y.: Research of soil–water characteristics and shear strength features of Nanyang expansive soil. Eng. Geol. 65(4), 261–267 (2002)CrossRefGoogle Scholar
  10. 10.
    Shao, L.T., Guo, X.X., Liu, S.Y., Zheng, G.F.: Effective Stress and Equilibrium Equation for Soil Mechanics. CRC Press, Boca Raton (2017)CrossRefGoogle Scholar
  11. 11.
    Ye, W.M., Zhang, Y., Chen, B., et al.: Shear strength of an unsaturated weakly expansive soil. J. Rock Mech. Geotech. Eng. 2(2), 155–161 (2010)CrossRefGoogle Scholar
  12. 12.
    Zhan, L.T., Ng, C.W.: Shear strength characteristics of an unsaturated expansive clay. Can. Geotech. J. 43, 751–763 (2006)CrossRefGoogle Scholar

Copyright information

© Springer Nature Switzerland AG 2019

Authors and Affiliations

  • Longtan Shao
    • 1
    Email author
  • Xiaoxia Guo
    • 1
  • Tiande Wen
    • 1
  • Boya Zhao
    • 1
  1. 1.State Key Laboratory of Structural Analysis for Industrial Equipment, Department of Engineering MechanicsDalian University of TechnologyDalianChina

Personalised recommendations