STUDY ON DEFORMATION CHARACTERISTICS OF EXISTING BALLASTLESS TRACK APPLYING ROADBED IMPROVEMENT

Abstract

 In order to reduce the cost of track maintenance, ballastress track for existing was developed, in which the ballast voids were filled with cement grout. However, some constructed ballastress tracks require repair within a few years after operation on the soft roadbed. Therefore, in this study, we developed a construction method that can improve the roadbed simultaneously with the construction of the ballastress track, when the ballastress track installed on a soft roadbed. We evaluated the deformation characteristics of the ballastress track with improved roadbed by full scale loading tests. It was also found that the amount of plastic settlement of ballastress track could be evaluated by repeated triaxial compression test of subgrade materials. Furthermore, we confirmed the effect of reducing the stress generated in the existing ballastless track by applying the roadbed improvement.