Abstract:Rheologic characteristics of soil are very important in soil mechanics. Almost every aspect of research on soil mechanics deals with rheologic characteristics of soil. Although more than half century has passed, study on rheologic characteristics of soil only made a very small progress, which was due to the two facts: (1 ) the complexity of rheologic characteristics of soil; (2) the research methods based on experimental fOrmulas. Based on thermodynamic theory and endo-chronic theory, a new intrinsic constitutive equation for rheologic characteristic of soil was developed, which combined with two groups of internal state variables and their correlative intrinsic time. The new intrinsic constitutive equation did very well in predict essential features of the rheologic behavior of soil, with which the dilatancy of soil during the rheologic process could be described.

Key words:  soil mechanics; rheology; endo-chronic theory; viscoplasticity