Articles | Volume 16, issue 12
Research article
29 Nov 2016
Research article |  | 29 Nov 2016

Development of fragility curves for railway embankment and ballast scour due to overtopping flood flow

Ryota Tsubaki, Jeremy David Bricker, Koji Ichii, and Yoshihisa Kawahara

Abstract. Fragility curves evaluating a risk of railway embankment fill and track ballast scour were developed. To develop fragility curves, two well-documented events of single-track railway washout during floods in Japan were investigated. Type of damage to the railway was categorized into no damage, ballast scour, and embankment scour, in order of damage severity. Railway overtopping water depth for each event was estimated based on well-documented hydrologic and hydraulic analyses. Normal and log-normal fragility curves were developed based on damage probability derived from field records and the estimated overtopping water depth. A combined ballast and embankment scour model was validated by comparing the results of previous studies and the spatial distribution of railway damage type records.

Short summary
Railways in floodplains and coastal areas are frequently damaged by floods. Railway systems suffering scour damage face interruption of operation for weeks. This substantially limits the socioeconomic activities that rely on the transport service provided by the railway. This paper proposes new fragility curves for railway embankment and ballast scour. This contributes to expand our ability to estimate risk of flood hazard on our society more holistic than ever.
Final-revised paper