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.

Monitoring the Response of Roads and Railways to Seasonal Soil Movement with Persistent Scatterers Interferometry over Six UK Sites

“…Apart from [20,25], there is limited work reporting investigation of the relationships between major soil group type and infrastructure movement using PSI, particularly in the UK, so limited direct comparisons can be made. Several papers have investigated infrastructure deformation using the PSI technique [3,8,14], but these studies use PSI to assess the structural condition of infrastructure assets in areas of known continual ground deformation.…”

“…The other sites were selected based on the high potential for infrastructure responses to shrink swell cycles of soil. Sites selected in Eastern England have the highest shrink-swell potential of soils in England, based on the largest annual Soil Moisture Deficit (SMD) [25]. Pritchard, O.G.…”

“…Pritchard, O.G. et al [25] notes that Eastern England has the highest SMD rates in the country, calculated from the daily precipitation, evapotranspiration and drainage of the soil, and describes the amount of water needed for the soil to return to field capacity (in mm). Furthermore, we include the response of railways to peat soils deformation in the Peterborough area, which is of importance given the significant peat wastage rates described in [26].…”

“…Sites selected in Eastern England have the highest shrink-swell potential of soils in England, based on the largest annual Soil Moisture Deficit (SMD) [25]. Pritchard, O.G.…”

Soil geohazard mapping for improved asset management of UK local roads

“…Longitudinal cracking is the predominant mechanism of road failure recorded in the majority of studies (Puppala et al, 2011). Cracking of the road surface can often lead to a "vicious cycle" of successive shrink-swell episodes within the substrate, resulting in rapid deterioration of road surfaces and in the worst-case scenario car accidents and fatalities (Jegede, 2000). Wanyan et al (2015), reporting on a Texas road survey, found that substrate moisture fluctuations represent the main perceived reason for longitudinal cracking of road surfaces, further exacerbated by poor drainage (Zumrawi, 2015).…”