ABSTRACT
Successive soil structures are formed, developed and destroyed during shear deformation of soils; the soil structures are characterized by mutual arrangement of particles, contact points among them and forces acting in these points. Transition from one soil structure to the other occurs as a jump. Shear deformation takes place on four levels: Molecular, particle, structural and aggregate. The creep process on the first two levels is deterministic, on the next level it is accompanied by jump-like soil structure reorganizations and is stochastic, on the aggregate level it obeys to causality characterized by intrinsic curve. Four phases of the creep process are distinguished according to relationship between time and shear strain rate of soil structures: Mobilization (inverse proportionality), acceleration (direct proportionality), stabilization (inverse proportionality) and rupture (constant). At low shear stresses only one phase of mobilization-stabilization is observed, at intermediate shear stresses – three phases: Mobilization, acceleration and stabilization, and at the high shear stresses – two phases: Mobilization and rupture. Concentration of the creep with time is the consequence of these processes. The static viscosity is an effective characteristic of the rheological properties of soils. It is a constant for the given soil and normal stress. Taking into consideration these conclusions will increase the information gained from the soil testing and reveal the reserves of the soil shear strength.
