ABSTRACT

Subgrade is a global foundation upon which railway structure is constructed on a track. It has paramount importance due to its influence on track general behavior in service. In order to present a good performance, subgrade must have appropriate stiffness and enough bearing capacity to resist the stresses and avoid excessive plastic deformations that influence the superstructure components deterioration. Special attention must be paid to a subgrade of heavy haul tracks, which are normally employed for commodities transport and subjected to different operational conditions in terms of speed, loads, wagon number, etc. On these particular conditions, it is reasonable to consider an increase in the track components degradation rate. Aiming to evaluate the structural condition of a subgrade, laboratory and in situ tests can be performed. This study was based on tests to evaluate the mechanical condition of a typical tropical soil, addressing a subgrade rehabilitation process in a heavy haul track. This study included physical characterization and resilient modulus tests in laboratory, as well as two different in situ tests, namely Dynamic Cone Penetrometer (DCP) and Light Weight Deflectometer (LWD). In general, in situ tests results showed that the materials in both sections have high stiffness confirmed by the resilience modulus laboratory tests. However, due to the used methods, it is necessary to evaluate a larger number of sections to then, determine a correlation between the elastic modulus from the LWD test and the California Bearing Ratio (CBR) from DCP test. Finally, among the three different soils classification methods verified, the MCT methodology is the one that best suit to the evaluated material.