Anisotropic Resilience Modulus Model of Granular Materials Based on Particle Characteristics

Granular materials are widely used for base or subbase in pavement structure. It typically exhibits strong anisotropic properties which is related to stress state and particle characteristics. Conventional design procedure for flexible pavements underestimates the anisotropy of resilience modulus. This study established an anisotropic resilience modulus model for granular materials, considering gradation and particle shape characteristics. Vertical and horizontal resilience modulus of certain granular materials was measured via self-developed triaxial tests, to obtain corresponding model parameters and anisotropic coefficient. Gradation and particle shape models were established to quantify the granular material characteristics, and the parameters were regressed. Particle shapes were obtained via image processing, and the ratio (η) of particle sphericity to roundness was chosen as a shape parameter. Results show that η increases with the dwindling of particle size, and the average values of η for graded gravel and natural laterite are 0.54 and 0.63, respectively. The η distribution curves indicate that the proportion of relatively anisotropic particles, rather than extremely anisotropic particles, results in the difference of particle shape characteristics. The regression relationship between anisotropic calculation parameters and model parameters of vertical resilience modulus, gradation and particle shape was established. Thus, the horizontal resilience modulus and anisotropic coefficient can be predicted, via conventional resilience modulus tests and gradation and particle shape analysis. This study shows that the anisotropy of granular materials, decreases with the increase of coarse particles and the uniformization of gradation curve, and increases with the increase of anisotropic particles and the polarization of η distribution.

Language

  • English

Media Info

  • Media Type: Digital/other
  • Features: Figures; Photos; References; Tables;
  • Pagination: 21p

Subject/Index Terms

Filing Info

  • Accession Number: 01763443
  • Record Type: Publication
  • Report/Paper Numbers: TRBAM-21-04132
  • Files: TRIS, TRB, ATRI
  • Created Date: Dec 23 2020 10:59AM