Dynamic behaviour of unsaturated porous media: governing equations using the Theory of Mixtures with Interfaces (TMI)
✍ Scribed by Muraleetharan, Kanthasamy K.; Wei, Changfu
- Publisher
- John Wiley and Sons
- Year
- 1999
- Tongue
- English
- Weight
- 206 KB
- Volume
- 23
- Category
- Article
- ISSN
- 0363-9061
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✦ Synopsis
Theory of Mixtures with Interfaces (TMI) is used to develop "eld equations governing the behaviour of unsaturated porous media under dynamic loading conditions. Interfaces existing between bulk phases in unsaturated porous media are explicitly considered in the TMI. Volume fractions and area densities are introduced as independent constitutive variables. A new de"nition for the total stress that explicitly includes interfacial e!ects is deduced. Thermodynamic restrictions are used to derive the constitutive relationships. It is found that there exists a well-de"ned potential (i.e. Gibbs' thermodynamic potential) to drive the #ow of the #uids. E!ective stress for unsaturated soils is theoretically shown to dependent not only on the degree of saturation but also on the stress path and soil type. Theoretical basis for the use of two stress state variables, net stress and suction, instead of a single e!ective stress is provided. The soil}water characteristic curve is shown to be none other than the linear momentum balance equation of all the interfaces. Realistic functional forms are suggested to take into account the variation of suction when the solid skeleton undergoes deformation. The "nal set of governing equations presented are easily implementable into "nite element methods and can be used to analyse problems such as the earthquake loading of compacted soil embankments.