In 2012, South Gloucestershire Council received a report of a landslip on a cutting slope separating this highway from a property near Olveston. In order to minimise the risk of further slippage, a slope stabilisation design was produced and CAN was commissioned to implement the soil nail system to ensure long term stability of the slope.

CAN installed 141 self-drilling hollow bar soil nails up to 5m in length using an excavator mounted drill mast working from the road level during a full closure. These were designed to tie back 500m2 of TECCO® G45/2 netting and DYWI® Mat erosion matting. Upwardly inclined drains comprising a perforated pipe with an outer geotextile filter layer were also installed to allow water run off without causing damage to the slope.

Rope access techniques were used to provide a safe access method for working on the steep slope whilst drilling soil nails into the embankment and installing the drape netting and head plates over the face.

Field studies conducted by ecologists revealed breeding populations of great crested newts in the near-by areas. Working closely with the local council and ecologist team, all measures were taken to ensure their habitats were not disturbed during the works, including a diversionary barrier around the worksite and daily checks on all CAN plant and materials to ensure the newts hadn’t sequestered themselves within our site.

CAN also conducted acceptance tests to guarantee that the installed soil nails met the quality criteria required to ensure maximum stability. Working closely with Tarmac and South Gloucestershire Council, CAN was able to meet the demands of the job successfully and within the agreed programme.

Duration:   6 weeks

Client:         Lafarge Tarmac for South Gloucestershire Council

Location:    Olveston, South Gloucestershire