Abstract:

Dilatancy is an important mechanical issue in the study on strength and deformation of coarse granular materials. It is governed by microscopic factors such as particle arrangement and inter-particle pressure, and hence is affected by macroscopic variables including relative density and stress state. In this article, research progresses in the dilatancy of coarse granular materials under complex stress conditions are reviewed from the aspects of mechanical properties, strength criteria, critical state, and dilatancy behavior. Future trends in research are outlined as follows: 1) Laboratory investigation via large-scale true triaxial tests and theoretical analysis on the dilatancy of coarse granular material would drive advancements in constitutive modeling. 2) Study on the stress-deformation facilitates the dilatancy equations under conventional triaxial condition developing into that under complex stress condition, thereby unifying strength and deformation issues. 3) Coupling stress state and void ratio with state parameters offers a systematic approach to assessing the compactness state of soils and their dilatancy behavior, potentially reducing the reliance on multiple material parameters. The integration of state parameters and stress paths indicates a more scientific and systematic approach in the research on the mechanical properties of coarse granular materials.

Key words: coarse granular material, dilatancy, true triaxial test, strength criterion, state parameter