Prediction of the Undrained Shear Strength of Pavement Subgrade using Falling Weight Deflectometer

摘要

Both stiffness and strength of pavement subgrade have an important contribution to the long-term performance of a pavement structure. As such, the need for accurate and reliable pavement foundation characterisation is essential in ensuring adequate quality control on compaction during subgrade construction. To meet the objective, falling weight deflectometer (FWD) has been employed for the study and the evaluation of the structural characteristics and performance of the pavement foundation. The FWD tests Were carried out at a test section near USJ Toll Plaza of the Central Link of the North-South Expressway. The development of a simplified subgrade model for assessing the pavement foundation using FWD is presented. The structural response and performance of the pavement foundation are evaluated at low amplitude impulse load. Layered elastic theoiy-based ELSYM5 (1986) program is utilised to back-analyse the low strain elastic moduli of the pavement subgrade. The study shows that there are unique relationships between the undrained shear strength of the subgrade and the FWD deflection parameter. A useful engineering relationship has been derived for the prediction of undrained shear strength of pavement subgrade using FWD deflection parameter. A relationship has also been developed between the back-analysed elastic modulus of the pavement subgrade and the FWD deflection value.