Applicability of unsaturated soil mechanics for resilient modulus: Case study of a Korean experience

In 2004, the KHC test road was constructed to evaluate long-term performance of the pavement under actual road environment in Korea, and pavement responses were monitored. To consider a mechanical behaviors of foundation materials, the resilient modulus was adopted for the subbase and subgrade layer instead of CBR. Therefore, a need exists that the resilient modulus should combine the effects on mechanical and environmental loadings reasonably. For this, stress-and moisture-dependent nonlinear resilient modulus model is introduced using unsaturated soil mechanics approach. Then the proposed model was evaluated based on the various laboratory tests based on KHC test road conditions. Some of these efforts are illustrated in this paper by a combination of field observations from a Korean experience on KHC test roads and estimation made by stress and moisture-dependent analyses guided by theory which explains the suction stress.