WEEKS GEOTECHNICS has teamed up with consultant Owen Williams Railways to provide a new service for assessing, remediating and maintaining geotechnical structures on railways.
Owen Williams Railways had already developed an assessment management contract with Railtrack in the South-east, focused on a cost-efficient long-term structures maintenance programme.
Weeks was brought on board to apply the same maintenance approach for geotechnical structures, including cuttings and embankments.
These combined capabilities offer a genuine 'one-stop-shop'approach, says Weeks'director Jeff James, providing 'best value and low longterm maintenance of the structures'. A rapid response service is provided, which includes a 24-hour emergency hotline.
The process was tested at three sites with a history of cutting instability. In each, historical deterioration of crest drainage had caused slope failure with near surface translations and scour.
Weeks confirmed the failure mechanisms and came up with a design solution for construction. The firm carried out desk studies, walkover surveys and intrusive investigation where needed before developing the design.
James says the key challenge was 'to provide a low-cost, high-value fix that reduced geotechnical and operational risks to acceptable levels, but achieved a buildable solution in often difficult environments'.
The common problem at each site was inadequate crest drainage to the cuttings, making the sites vulnerable to heavy rainfall. Typically, this has caused near surface translation or scour of the cutting slope with debris and flooding at track level.
Proposed designs were typical 'rail solutions', to cope with limited access and to minimise the impact on rail traffic. These included renovation or renewal of crest drainage discharging to independent surface water systems, gabion baskets and mattresses to stabilise near surface scour paths, installation of formal surface water overflow systems connected into trackside drainage and renovation of trackside drains.