Abstract: The strength and deformation characteristics of rockfill materials are known to be closely related to their gradations. In order to predict the mechanical behavior of rockfill materials with different initial gradations, the influence of gradation on the mechanical properties of rockfill materials is first discussed within the framework of critical state constitutive theory. Subsequently, a method is proposed for rapidly predicting the initial and critical state void ratios for given gradations. Finally, by incorporating a state-dependent elastoplastic constitutive model, a prediction method for the gradation-related mechanical characteristics of rockfill materials is established. The results indicate that a good linear relationship exists between the minimum void ratio e_min and the critical state void ratio e_cs under low-stress conditions. Utilizing a particle packing algorithm, the critical state position of rockfill materials with specific gradations in the void ratio-pressure (e-p, e is the void ratio of the rockfill material in its current state, and p is the mean stress) space can be reliably predicted. Ultimately, this proposed prediction method facilitates the calibration of constitutive model parameters based on the test results of rockfill materials with known gradations, which subsequently allows for effective prediction of the mechanical behavior of other rockfill materials with different specified gradation profiles.

Key words: rockfill material, gradation, mechanical behavior, critical state, state-dependency