Abstract:

Current research indicates that the stress path of rockfill during dam construction can be approximated as that the principal stress ratio keeps constant (q/p =constant); and it will become a complex stress path (dq/dp =constant) upon reservoir filling. Drained tests were conducted in large scale triaxial apparatus under two types of stress path, which were the deviatoric compression tests under the paths of constant stress ratio and the shear tests under complex stress paths. According to the test results, an incrementally nonlinear elastic model of rockfill considering the effect of stress path was proposed, which including three modulus functions could describe not only the stress-strain characteristics of rockfill under constant stress ratio, but also the constitutive relations of transitional stress paths according to the appropriate compliance matrixes based on the transitional path feature. From the simulations of the test curves, it is shown that the model can well predict the stress and deformation behaviors of rockfill under complex stress paths.

Key words: constant stress ratio, complex stress path, modulus, constitutive relation