ABSTRACT
ABSTRACT: This paper analyzes the performance of bituminous subballast against environmental actions as an alternative to the granular subballast layer usually used in European high-speed tracks. The comparison between both designs is made in terms of the vertical displacements and its seasonal variation as well as the capability of maintaining the moisture content along the year. Two methods were used for the calculation of the relative humidity/suction in the soil depending on the subballast. The first assumes that the soil would have a given percentage of the atmospheric relative humidity and uses the Barcelona Basic Model (BBM) to calculate the deformations associated to it. The second method uses the numerical finite elements program CODE_BRIGHT to perform this calculation. From the different theoretical approaches developed, it is found that the bituminous subballast should allow an important reduction in the seasonal vertical displacements within the trackbed, reducing therefore overall track maintenance needs.
