ABSTRACT
This paper describes some aspects of the composition of soils, the kinematics of the solid phase, and the movement of the liquid and gaseous phases. In section 2 concepts describing the composition of the soil are introduced. Section 3 deals with the deformation and motion and the balance of mass of the solid phase. In section 4 the balances of mass and momentum for the liquid and gaseous phases are introduced. In sections 5 and 6 some aspects of fluid flow in, respectively, rigid and non-rigid soils are discussed. In section 7 some conclusions are given and possible extensions of the theory are mentioned
