The Implications of Predicted Climate Changes on the Stability of Highway Geotechnical Infrastructure: A Case Study of Field Monitoring of Pore Water Response

The future, long-term, stability of slopes in cuttings and embankments is of increasing concern among geotechnical engineers in the UK. A study of the motorway earthworks in the UK (Perry, 1999) conservatively estimates that three times as many slopes are likely to fail than have failed to date if no preventative measures are taken to account for climate change and progressive failure. Elevated pore-pressures as well as pore-pressure cycling are both responsible for decreases in soil strength and the stability of slopes (Potts et al 1997). Recent studies in Northern Ireland have been directed towards investigating the effect of rainfall events on the long term stability of cuttings on both road and rail infrastructure. Several cuttings in glacial till (Hughes et al. 2001, Clarke et al. 2005) have been investigated in detail and long-term monitoring of near surface pore pressure changes have been recorded and correlated with rainfall events. Monitored short-term (hourly) and long-term (annual) fluctuations in pore pressure response due to climatic forcing have been simulated in order to identify the properties and processes controlling pore-pressure dynamics within the cutting slopes. The paper presents the field monitoring data of pore pressure change correlated with rainfall events for the north of Ireland. The effect of rainfall events on stability has been discussed and the implication of climate change on the geotechnical infrastructure in the UK, such as more intense winter rainfall events and drier summer weather, have been outlined.