Measurement and Evaluation of Subgrade Soil Parameters: Phase 1 - Synthesis of Literature

摘要

A key material property used in the mechanistic-empirical pavement design guide (MEPDG) is the resilient modulus (Mr), which either can be obtained from experimental testing or can be backcalculated from other measured soil properties. The determination of a representative Mr value for a given subgrade, considering seasonal variations and testing intricacies, is not an easy or straightforward task. Over 30 different correlations equations were reviewed in this study. Selected equations were further examined using data from two MDT soil survey reports. Results from the literature review and preliminary data evaluation indicate there is little to no consistency between equations for predicting Mr from soil index and classification properties. Most of the equations were developed from relatively small sample sets and often for region-specific soil types. Until a more detailed assessment is conducted, the authors discourage the general use of Mr correlation equations without prior testing and verification of the suitability and reliability of the modulus estimates.