Abstract
Unsaturated soil is a three-phases assembly, i.e., soil particle (solid phase), pore-air (gas phase), and pore-water (liquid phase). In this paper the number of soil particles per unit volume, the number of contact points of soil particles per unit area and the number of contact points per a soilparticle (coordinate number) are used as basic quantities to establish a new comprehensive soil mechanics for unsaturated soils, which can organically analyze the water retention, pore-air permeability, pore-water permeability, compression and shear behaviors based on the statistics and probability theory. For pore-air and pore-water the elementary particulates model is introduced to derive the soil-water characteristic curve and the coefficients of pore-air and pore-water permeability. Forsoil particles the Markov process is applied to analyze the continuous change in contact angles at contact points of soil particles and the ratio of disappearance&appearance is introduced to estimate the discontinuous change in the number of contact points.
