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Work input for unsaturated soils considering interfacial effects
Author(s) -
Liu Yan,
Wei ChangFu,
Zhao ChengGang,
Fang Qian,
Li Jian
Publication year - 2018
Publication title -
international journal for numerical and analytical methods in geomechanics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.419
H-Index - 91
eISSN - 1096-9853
pISSN - 0363-9061
DOI - 10.1002/nag.2784
Subject(s) - degree of saturation , effective stress , saturation (graph theory) , constitutive equation , work (physics) , stress (linguistics) , soil water , capillary pressure , mechanics , geotechnical engineering , deformation (meteorology) , function (biology) , mathematics , porous medium , materials science , thermodynamics , porosity , physics , finite element method , engineering , environmental science , soil science , linguistics , philosophy , combinatorics , composite material , evolutionary biology , biology
Summary In this research, the interfacial energy is taken into account in the deformation work for unsaturated soils. Based on porous media theory, the thermodynamic balance equations for each phase and the interface are used to derive the work input for unsaturated soils. The work input equation serves as the basis and starting point for the choice of stress state variables, based on which the conjugate stresses and strain increments are derived. The influences of the interfaces on the effective stress and the constitutive law for the liquid phase are then discussed based on the work input equation. The effective stress can be expressed as Bishop's type, and the effective stress parameter is shown to be a function of both the degree of saturation and the interfacial area. The constitutive law for the liquid phase under dynamic condition is also presented. The relationship among interfacial area, saturation, and capillary pressure is proposed to calculate the value of the effective stress. Experimental data obtained from literature are used to validate the proposed model equations. Results show that our findings are in accordance with the existing research. Unlike the phenomenal study, our research has a rigorous theoretical basis, which lays a foundation for further research of unsaturated soils considering the interfacial effects.