Engineers Australia

Effects of size, humidity and time in crushable granular materials

Assistant Professor Carlos Ovalle


Granular materials subjected to relatively high stresses can undergo particle breakage. Some examples in Geotechnical Engineering include rockfills at the base of high dams, sands at the tip of driven piles, and sandy fills in rock mass discontinuities. Particle breakage can lead to increased compressibility and deformations that cause damage in civil works.

It is known that crushable granular materials could have size effects due to the fact that, like most fragile materials, the fracture resistance of rock aggregates is inversely proportional to their size. However, due to the scarcity of empirical data, size effect on coarse rockfill materials are still not well recognized. In addition to this, some authors have recently shown that there is a creep effect in granular materials and that the magnitude of these delayed deformations increases with the material humidity. This could be explained by the stress corrosion phenomena at the rock aggregate scale. The factors influencing the magnitude of creep deformations such as particle size, mineralogy, and stress path have not yet been studied in depth.

In this presentation, recent results concerning the effects of size, humidity and time are presented. Results of recent and ongoing research are shown, as well as research perspectives on the degradation process of the mechanical properties of sands and rockfills.

About Carlos Ovalle

Carlos Ovalle was awarded a Bachelor Degree in Civil Engineering from the Santa María Technical University in Chile, he received a Master of Science in Geotechnical Engineering from the École Centrale Paris and a Ph.D. Degree from École Centrale de Nantes, France. He has 15 years of experience in Geotechnical Engineering and since 2013 he is Assistant Professor in the School of Engineering of the Catholic University of Chile, where he has taught courses on Soil Mechanics, Experimental Geotechnics, and Mine Waste Geotechnics, among others. His research area is experimental geotechnics and hydro-mechanical degradation of granular materials, applied to mining wastes, rockfills, and granular soils.

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