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INfrastructure Earth Structures Inclement Weather Response Dr Fiona Thomson, London Underground, Transport for London describes London Underground’s approach to inclement weather response. Introduction (Maizza, 2009). This study included The London Underground network gaining advice from Network Rail. includes 210 km of cuttings and embankments. These are subject to an In 2010 London Underground continued inspection and assessment regime, which this review to further quantify risk records their condition and informs the levels and recommend mitigating actions projects and maintenance works required (Richards, 2010). based on the risks presented. Inclement weather and However, while knowledge of inherent climatic indicators structural condition is clearly essential, Inclement weather as affecting earth risk is also present from transient, structures is considered to be high external effects. Of these, inclement intensity rainfall over short durations, weather is considered particularly prolonged periods of above average rainfall Figure 1 Colindale Embankment Failure, 1994 significant. and temperatures falling below freezing. London Underground has a long- Soil Moisture Deficit (SMD) can be established corporate plan for dealing considered as a second order indicator, as with adverse weather and the impacts it has rainfall as a pre-cursor. on service. However, a more detailed perspective on the implications for earth Changes in rainfall patterns need to structures assets was sought. This was be considered using the most recent with a view to developing both individual projections (UKCIP 2009). It seems asset and holistic knowledge, to inform at probable that rainfall intensity will both the tactical and strategic levels. increase, or rather the frequency of higher intensity events. In 2009 Metronet under the PPP contract with London Underground commissioned Climatic indicators were examined with Atkins to identify earth structures at respect to earth structures in 2009 risk from the effects of extreme weather (Parry, 2009). 6


evolutionwinter2012
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