Conventional or classical soil mechanics assumes s
Conventional or classical soil mechanics assumes soil media to be completely water or air saturated. This is a typical example of a two phase media consisting of soil solids and water/air. The assumption of two phases considerably simplifies the mathematical quantification of the complex phenomena that take place in porous media. Off late, geotechnical and geoenvironmental engineering problems require the concept of three or multiphase behaviour of soil for realistic solution of several field situations. For example, a partially saturated soil is a three phase porous media consisting of air, water and soil.