Fragility curves for rainfall-induced shallow landslides on transport networks

Many of the earthworks assets on rail transport networks were constructed in the 1800s and have thus operated for periods far in excess of their expected service life. Incidences of failure-- particularly shallow planar landslides-- are increasing, in part due to the effect of more intense and longer duration rainfall events. Network owners have difficulty in targeting scarce resources to reduce risk across networks. This paper proposes a methodology for developing fragility curves for rainfall-induced landslides on transport networks. Fragility curves provide the probability of exceedance of different limit states for a given hazard considering a range of magnitudes. In this paper, the vulnerability of slopes as expressed by a loss of performance is quantified for rainfall events of various intensities and duration. The approach expands upon probabilistic slope stability analysis and provides a rational logical framework for considering how vulnerable a slope is to rainfall-induced failure. Key words: fragility curves, vulnerability, probabilistic analysis, shallow landslides, rainfall, transport. Bon nombre des actifs de terrassement sur les reseaux de transport ferroviaire ont ete construits dans les annees 1800 et ont donc fonctionne pendant des periodes depassant de loin leur duree de vie prevue. Les incidences de defaillance, en particulier les glissements plans peu profonds, augmentent, en partie a cause de l'effet de pluies plus intenses et de plus longue duree. Les proprietaries de reseaux ont de la difficulte a cibler des ressources limitees pour reduire les risques sur les reseaux. Cet article propose une methodologie pour developper des courbes de fragilite pour les glissements de terrain induits par les precipitations sur les reseaux de transport. Les courbes de fragilite fournissent la probabilite de depassement de differents etats limites pour un danger donne en considerant une plage de grandeurs. Dans cet article, la vulnerabilite des pentes, exprimee par une perte de performance, est quantifiee pour les evenements pluvieux de differentes intensites et durees. Cette approche elargit l'analyse probabiliste de la stabilite des pentes et fournit un cadre logique rationnel permettant d'evaluer la vulnerabilite d'une pente a une defaillance provoquee par les pluies. [Traduit par la Redaction] Mots-cles: courbes de fragilite, vulnerabilite, analyse probabiliste, glissements de terrain peu profonds, precipitations, transport.
Introduction In Europe there has been substantial variation in weather patterns over recent decades that affect the performance of engineered slopes. Since 1950 mean annual rainfall levels have increased by [...]