Laboratory Assessment to Correlate Strength Parameter from Physical Properties of Subgrade

Subgrade soil is an essential component for design of both flexible and rigid pavement structures. Laboratory assessment of California Bearing Ratio beneficial for design of flexible pavement, Coefficient of subgrade reaction K-Value required for design of rigid pavement, raft footing and unconfined compressive strength (UCS) is useful for determination of shear strength parameter of subgrade are time consuming and demand significant effort but mandatory. This study considers the use of multiple variable regression analysis (MLR) to predict the California Bearing Ratio (CBR), Coefficient of subgrade reaction K-Value, unconfined compressive strength, Dynamic Cone Penetration (DCP) from maximum dry density (MDD) and optimum moisture content (OMC) of subgrade. This paper presents the empirical correlations developed from multiple variable regression analysis from test results obtained from experimental investigation of soil sample taken from different locations of Gujarat region. The formulations are validated using other sets of tests data. The developed empirical correlations maybe useful in quick determination of strength parameters of subgrade from physical properties.