Numerical investigation of the time size effect of high rockfill geostructures

Abstract The creep parameters of rockfill are usually derived from creep test in the laboratory, in which the loading period before the creep stage is much shorter than the construction period in the field. This difference might cause underestimation of the long-term settlement of high rockfill geostructures if an elastic-viscoplastic model based on isotach assumption is adopted. This paper aims to investigate this hypothesis. A time-dependent strain hardening model is proposed to simulate the creep behavior of rockfill based on the relationship between the macro- and micro-responses of crushable particles during triaxial creep test revealed by previous DEM study. The results of triaxial creep tests on various granular materials are used to validate the model. The time size effect is highlighted by comparing the predicted long-term deformation of rockfill using the proposed model and an existing isotach model. The results show that the isotach model tends to underestimate the long-term deformation of high rockfill geostructures in the field compared with that of the proposed model, even when both models are calibrated against the same laboratory test results.