Fracture Mechanics and Rockfill Dams
E. E. Alonso
Manuel Rocha Lecture
Soils and Rocks, São Paulo, 37(1): 3-35, January-March, 2014 | PDF
Rockfill behavior is dominated by particle breakage, a phenomenon which is analyzed from the perspective offered by the subcritical propagation of cracks within individual particles. Propagation velocity depends on stress concentration in particles as well as on the ambient Relative Humidity (RH). RH controlled oedometer and triaxial tests are reviewed and constitutive models reproducing the main features of observed behavior are outlined. The relevant issue of size effects is then introduced and some rules and possibilities to account for these effects in practice have been given. The Distinct Element Method is also a powerful tool to investigate rockfill behavior. Recent developments are described. The model developed incorporates particle breakage, delayed effects and the action of water. In the final part two real cases are presented: the response of a high rockfill embankment against a four year long rainfall regime and the analysis of Beliche dam. The lecture closes by a general discussion of partial saturation in granular materials ranging from coarse granular aggregates, such as rockfill, to clayey soils in an attempt to provide an integrated overview of water effects in soils.
Invited Lecture, No discussion.