Small-strain stiffness of the Pampeano Formation

Alejo Sfriso, Sagüés, P., Quaglia, G., Quintela, M. & Ledesma, O.
Sunday, April 1, 2007
First presented: 
University of Buenos Aires
Published paper

Buenos Aires, Argentina, rests on a loess deposit named Pampeano Formation. Foundations of buildings, industrial facilities, major infrastructure projects, metro tunnels and a nuclear power plant lay on this deposit. Pampeano soil is also used as a construction material for sub-bases, fills and embankments. A research program was established at the University of Buenos Aires to measure the small-strain nonlinear behavior of the material in the laboratory. A data acquisition system using LDTs was manufactured and installed in the triaxial apparatus, and a series of drained triaxial compression tests and one-dimensional compression tests was performed on both undisturbed and compacted samples. In this paper, the Pampeano Formation is briefly described, the data acquisition system is outlined, and some test results are presented. Data confirms the pressure dependency of the Young’s modulus and modulus reduction curves for compacted samples and shows that undisturbed samples follow the same trend, a fact that was neither expected nor assumed in routine design due to the cementation of the material. Results obtained so far and the main objectives of future research work are discussed.

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