Abstract
The two-phase instability of saturated elasto-plastic soils is investigated under plane strain conditions. This type of material instability is characterised by a non-homogeneous field of solid deformation with vortex-like patterns, which grows rapidly and is accompanied by a non-uniform flow of interstitial water exhibiting source-sink flow patterns. Three simple criteria are established to define the conditions for the onset of two-phase instability within elasto-plastic soils saturated with an incompressible fluid and subjected to plane-strain undrained loadings. The simplest criterion states that the onset of instability almost coincides with the peak deviator stress during undrained loading. This analysis shows that two-phase instability in elasto-plastic soils is different from strain localisation, strain softening and constitutive singularities. Two-phase instability is likely to emerge before shear bands in contractant elasto-plastic soils of the Mohr-Coulomb type. The study suggests that two-phase instability may disrupt numerical liquefaction analyses using elasto-plastic soil models, and thus prompts the need for further analytical and experimental investigations.
Original language | English (US) |
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Pages (from-to) | 389-398 |
Number of pages | 10 |
Journal | Geotechnique |
Volume | 51 |
Issue number | 5 |
DOIs | |
State | Published - Jan 1 2001 |
Externally published | Yes |
Keywords
- Constitutive relations
- Liquefaction
- Numerical modelling
- Pore pressures
- Theoretical analysis
ASJC Scopus subject areas
- Geotechnical Engineering and Engineering Geology
- Earth and Planetary Sciences (miscellaneous)