The first in the new TRL Insight Report Series is now available. "Improving the Stability of Slopes Using a Spaced Piling Technique" (Ref: INS001) by Derek R. Carder, Research Fellow, TRL Infrastructure Division. This Insight Report discusses the findings from a literature review, centrifuge and analytical studies, and two instrumented case studies to remediate clay slope on the highway network. The implications of the findings are discussed and design recommendations given.

Discrete piles are used to stabilise infrastructure slopes, especially where there is insufficient land to construct large toe berms or regrade slopes. Spaced piling can be used to steepen slopes with minimum landtake, and also for permanent, cost-effective reinstatement and repair of unstable or failed clay slopes.

This is particularly relevant to many motorway slopes, which are prone to shallow failures and are reaching a critical age for deep-seated failure to occur. The situation is made worse by the increasing incidence of heavy rainfall and flooding due to climate change, adding to the risk of softening of the clay. For these reasons, the Highways Agency initiated a comprehensive programme of research with TRL to investigate the potential of the piling technique.

To find out more about this publication please visit http://ct.newsletter.ihs.com/rd/cts?d=62-1442-663-722-3690-59473-0-0-0-1-2-267 or to purchase directly please call +44 (0)1344 328 038 and reference INS001.

For more information on TRL Reports please visit their website.