Soil geohazard mapping for improved asset management of UK local roads

Abstract

Abstract. Unclassified roads comprise 60 % of the road network in the United Kingdom (UK). The resilience of this locally important network is declining. It is considered by the Institution of Civil Engineers to be "at risk" and is ranked 26th in the world. Many factors contribute to the degradation and ultimate failure of particular road sections. However, several UK local authorities have identified that in drought conditions, road sections founded upon shrink-swell susceptible clay soils undergo significant deterioration compared with sections on non-susceptible soils. This arises from the local road network having little, if any, structural foundations. Consequently, droughts in East Anglia have resulted in millions of pounds of damage, leading authorities to seek emergency governmental funding. This paper assesses the use of soil-related geohazard assessments in providing soil-informed maintenance strategies for the asset management of the locally important road network of the UK. A case study draws upon the UK administrative county of Lincolnshire, where road assessment data have been analysed against mapped clay-subsidence risk. This reveals a statistically significant relationship between road condition and susceptible clay soils. Furthermore, incorporation of UKCP09 future climate projections within the geohazard models has highlighted roads likely to be at future risk of clay-related subsidence.

Time domain reflectometry (TDR) potential for soil condition monitoring of geotechnical assets

“…Deterioration, and failure mechanisms, of ageing geotechnical infrastructure have been attributed to a number of processes often related to changes in water content (including rapiddrawdown post-flooding, shrink-swell and desiccation, internal and surface erosion, as well as changes in pore-water pressure and (or) chemistry regimes) (Clayton et al 2010;Farewell et al 2012;Rajeev et al 2012;Glendinning et al 2014;Pritchard et al 2014Pritchard et al , 2015aPritchard et al , 2015bRosenbalm and Zapata 2017;Briggs et al 2017;Janik et al 2017;Stirling et al 2017). Hence, it is clear that water content is a key parameter influencing the performance of geotechnical assets.…”

How the impacts of burst water mains are influenced by soil sand content

“…Annual (2008-2013) Road Condition Index (RCI) SCANNER data were provided by highway engineers at the County Council. RCI is measured on a scale from 0 (good condition) to 315 (failed road) (Wallis, 2009;UK Roads Board, 2011;Pritchard et al, 2014bPritchard et al, , 2015b. Roads with RCI > 100 require maintenance.…”

“…damage to a road, and/or flooding of gas networks). Complex infrastructure failures can be cascading, be escalating or have a common cause (Rinaldi et al 2001). They can occur at a range of spatiotemporal scales and affect both physical and socio-political infrastructure.…”

“…Multi-infrastructure failures often result from a single failure in the crowded and heterogeneous array of co-located, aged and modern, interconnected and semi-automated infrastructure systems (Pritchard et al 2014a). These systems operate with physical, geographic, functional, cyber, policy and informational dependencies and interdependencies (Rinaldi et al, 2001;Zimmerman, 2004;Dudenhoeffer et al, 2006). These close relationships can make infrastructure vulnerable to complex failures.…”

“…Risks to infrastructure assets represent a key strategic risk for the water sector, and the heterogeneity of infrastructure assets, networks and the soil environment, in which they are buried, produces complexity for infrastructure operators and regulators tasked with providing robust and resilient levels of service (Rinaldi et al, 2001;Rogers et al, 2012;Chalker et al, 2018). With the limited awareness amongst infrastructure asset managers of system-of-systems thinking, which is rarely employed in asset risk assessments, and the limited communication between operators, governments and regulators, understanding of infrastructure interdependencies is often lacking (Young and Hall, 2015;Defra, 2011;Street et al, 2017; Committee on Climate Change, 2017).…”