Nonlinear stiffness and damping characteristics of gravelly crushed rock: Developing generic curves and attempting multi-scale insights

Kostas Senetakis*, Meghdad Payan, Haiwen Li, Mostafa Zamanian

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

9 Citations (Scopus)

Abstract

Gravelly soils and aggregates composed of crushed rock are commonly encountered in a variety of applications in geotechnical, transportation and infrastructure engineering projects, while gravel-sized materials, often in the form of soil mixtures, are also found in natural deposits in alluvial, glacial and shoreline environments. Despite the significant amount of research being conducted on the dynamic properties of soils, less attention has been given on the assessment and modeling of the behavior of gravel-sized materials, particularly in the range of medium strains, where stiffness and damping have a nonlinear relationship with strain amplitude. In the present study, laboratory data stemming from resonant column tests published in the literature are re-analyzed with emphasis on gravel-sized crushed rock of strong and hard grains and the range of small-to-medium strain amplitudes. The test samples had a mean grain size in the range of 1.5–10 mm and a coefficient of uniformity from 1 to 13. The stiffness reduction curves are studied by means of the Oztroprak-Bolton hyperbolic model and from the data analysis, correlations are developed for the reference strain, the linear threshold strain and the curvature coefficient, which are then incorporated as model parameters into the hyperbolic expression. For the damping increase curves, a correlation is proposed with respect to the stiffness values, taking into account normalizations for small-strain material damping. The analysis led to the development of generic stiffness reduction and damping increase curves which are compared with previous data and models published in the literature for a variety of soils. These comparisons show that for crushed rock of irregular-in-shape grains (i.e., elongated and angular grains), significant differences are observed on the stiffness reduction and damping increase curves between gravels and sands with the gravels displaying higher non-linearity with shifted reference strain and linear threshold strain to smaller values. This was particularly highlighted for uniform gravels compared with uniform sands, whereas a convergent of the generic curves between sands and gravels was observed for high values of the coefficient of uniformity. Thus, existing relationships developed on the basis of granular materials of rounded particles and specifically expressions on the basis of sand-sized materials should be cautiously used in the deformation analysis of problems involving gravelly crushed rock and natural soils of irregular-in-shape grains, particularly for uniform to poorly graded materials.

Original languageEnglish
Article number100668
Number of pages16
JournalTransportation Geotechnics
Volume31
DOIs
Publication statusPublished - 2021

Keywords

  • Crushed rock
  • Damping ratio
  • Gravel
  • Hyperbolic model
  • Resonant column test
  • Stiffness

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