Structural Hierarchy And Mechanical Properties Of Rock Mass. Part I: Structural Hierarchy And Strength Of Rock Mass

Rock mass has a complex structural hierarchy, which affects the physical-mechanical properties of rock mass very much. In this paper the relationship between viscosity and structural hierarchy is studied. The study shows that different structural levels correspond to different viscosity and characteristic strain rate. High viscosity and low strain rate correspond to macro-level, and meso- and micro-levels are characterized by low viscosity and high strain rate. Generally, with the increase of external actions, the strain rate grows also. Consequently, deformation and fracture gradually cover meso- and micro-levels, and viscosity gradually decreases. At high strain rate, viscosity is inversely proportional to strain rate. On the basis of analysis of viscosity at different structural levels, asymptotic intermediate approximation of viscosity at different levels is suggested. The approximation formulae transform to that at continental structural level and micro-level in the limit cases. This suggests that the approximation is adequate for the description of viscosity at different structural levels.