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Reinforcement of railway ballasted track with geosynthetic bags for preventing derailment

2013; Volume: 20; Issue: 5 Linguagem: Inglês

10.1680/gein.13.00023

1751-7613

Takashi KACHI, Mikihito Kobayashi, Masaki Seki, Junichi Koseki,

Grouting, Rheology, and Soil Mechanics

ABSTRACT: In order to prevent a long-term service interruption of Tokaido Shinkansen (bullet train) in Japan after an earthquake, various structures have been undergoing constant seismic retrofit. Despite these efforts, a Shinkansen train derailed during the Niigataken-Chuetsu earthquake in 2004. In order to prevent train derailments, it is important to prevent ballast from collapsing and flowing out during large earthquakes. Precast concrete blocks are in use on the Tokaido Shinkansen line for this purpose. However, precast concrete blocks have problems concerning workability and cost. Therefore, a new method of reinforcing ballasted track has been developed in which polymeric geomesh bags filled with ballast are stacked and strengthened by reinforcing bars. The results of shaking table tests confirmed that the reinforced ballasted track has sufficient seismic resistance against a severe seismic load matching the Tokai earthquake. Several durability tests were also performed, confirming that bags exposed to ultraviolet radiation for a long time have sufficient durability. Furthermore, a construction test on a commercial line demonstrated that the new method provides good workability. Thus the current study demonstrates that the seismic reinforcement of ballasted track using stacked bags and reinforcing bars is effective and practicable.