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Journal of Shanghai University >

2019 , Vol. 25 >Issue 2: 337 - 346

DOI: https://doi.org/10.12066/j.issn.1007-2861.1930

Research Articles

Constitutive model for unsaturated sedimentary soils based on SFG model

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  • Department of Civil Engineering, Shanghai University,Shanghai 200444, China

Received date: 2017-04-25

  Online published: 2019-05-05

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Abstract

The Sheng-Fredlund-Gens (SFG) model is modified by considering coupled water-retention and mechanical behavior to reflect the behavior of unsaturated sedimentary soils. The net stress is replaced with the average skeleton stress for stress state variable, and the influence of saturation on deformation is considered in the model. Based on test data of pre-consolidated clay at constant suctions for isotropic compression and triaxial shear, relationship between degree of saturation and void ratio is found, and the effect of deformation on saturation is considered in modeling the soil-water retention curve (SWRC). The loading collapse yield surface equation is derived from the volume change equation and SWRC equation. On the basis of a modified Cam-clay model, constitutive equations in triaxial stress state are derived with a unified hardening parameter that can describe shear contraction and dilatancy consistently. Using the same values of the model parameters, the hydraulic and mechanical behavior of unsaturated pre-consolidated clay can be consistently predicted under control of suction along isotropic compression and triaxial stress paths.

Key words： unsaturated soil; sedimentary soil; soil-water retention curve (SWRC); average skeleton stress; dilatancy

Cite this article

ZHANG Zhao, SUN Dean, GAO You . Constitutive model for unsaturated sedimentary soils based on SFG model[J]. Journal of Shanghai University, 2019 , 25(2) : 337 -346 . DOI: 10.12066/j.issn.1007-2861.1930

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