Performance Evaluation of Reinforced Concrete Roadbed for Slab Track on Clay Subgrade

A high bearing capacity for subgrade is essential to avoid excessive settlement in constructing slab tracks on earth structures. However, a soft diluvial clay layer was detected on part of a Tohoku-Shinkansen line under planning adjacent to the local town of Shichinohe. To address the problem, a double-line-integrated reinforced concrete roadbed was developed. We carried out detailed ground investigations to evaluate the performance of the concrete roadbed on the soft diluvial clay on which the slab track is to be constructed. We further carried out on-site cyclic loading tests involving the application of a vibration machine. Based on the results of these investigations and tests, we carried out FEM analysis to evaluate the deformation characteristics of the concrete roadbed. The results of the FEM analysis clarified that the double-line-integrated reinforced concrete roadbed was able to appropriately support slab track on the soft diluvial clay subgrade.