Particle mechanics modeling of creep behavior of rockfill materials under dry and wet conditions

Rockfill is an important construction material for infrastructure engineering, such as dams, railways and airport foundations, which display a long-term post-construction settlement. However, the main mechanisms for rockfill creep and weathering influence still remain poorly understood. Particle mechanics method is used to understand the rockfill creep process under dry and wet conditions. Different bond-aging models and wetting models that represent different degradation and weakening mechanisms are compared, in order to clarify the principle and secondary mechanisms for rockfill creep and weathering influence. The results show that rockfill aggregate breakage in terms of angularity abrasion is the main source for rockfill creep under dry state. Wetting can induce additional strain mainly due to the reduction of contact friction coefficient, i.e. lubrication, and the bond strength reduction just plays a secondary role in producing additional strain. The earlier the wetting occurs during rockfill creep, the more rapidly the rockfill becomes stable. The wetting–drying cycles can induce strain evolution in a ‘stepped’ way, which is in agreement with experimental observation. The practical implications from the modeling and the outstanding issues in this study are also discussed.