M_R-Moisture Relationships for Unsaturated Subgrade Soils

摘要

In recent years there has been an increased interest in determining the influence of moisture changes on the resilientmodulus (M_R) of subgrade soils beneath a pavement. Also efforts have been made to develop mathematical modelsthat predict the change in M_R values with moisture. These models are expected to account for seasonal variations insubgrade moisture content. The present study evaluates the variation of resilient modulus with post-compactionmoisture content of soils in Oklahoma. A series of specimens were compacted at optimum moisture content andthen tested for resilient modulus; other series of specimens were prepared at optimum moisture content and theneither wetted to higher moisture contents or dried to lower moisture contents prior to M_R testing. Results showedthat M_R-moisture content relationships varied with soil types. M_R decreased as moisture content increased andincreased with a decrease in moisture content. Finally, an M_R-moisture model is proposed that predicts the variationof resilient modulus with moisture contents. This model would be helpful in predicting the changes in bearingcapacity of pavements due to seasonal variations of moisture content.