Correlations of permanent strain and damping coefficients with resilient modulus for coarse-grained subgrade soils

ABSTRACT

In addition to the resilient modulus (M_R), the permanent deformation and damping characteristic of subgrade soils also need to be studied to properly understand the subgrade soil behaviour under dynamic traffic loading. Soils having relatively high resilient modulus may or may not have small permanent strains (ε_p) and lower damping (ξ). Therefore, it is necessary to study resilient modulus with both permanent strain and damping characteristics of subgrade soils. In this study, resilient modulus, permanent strain and damping of subgrade soils were measured under different repeated deviatoric loads and confining pressures. Statistical models were developed to correlate resilient modulus (k₁, k₂, k₃), permanent strain (α₁, α₂, α₃, α₄) and damping model parameters (β₁, β₂, β₃) with soil index properties. Models were also developed to correlate ε_p and ξ with subgrade soils M_R. Results showed that both permanent strain and damping decreases if resilient modulus increases for South Carolina coarse-grained soils.

KEYWORDS:

• Resilient modulus
• moisture content
• permanent deformation
• damping
• MEPDG

Acknowledgements

This article is based on research supported by the SCDOT and the FHWA under contract SPR 708: Calibration of the AASHTO Pavement Design Guide to South Carolina Conditions – Phase I. Any opinions, findings and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the SCDOT or the FHWA.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the SCDOT and the FHWA [SPR 732].