Around 1,000, hollow bar self- drilling soil nails are stabilising a section of cutting along the M6 Toll, being constructed by Carillion, Alfred McAlpine, Balfour Beatty and Amec.
Dywidag Systems International's R32N MAI hollow bars were installed in 10 rows into a 150m long by 8m high reinforced slope by subcontractor South Western Mining & Tunnelling in a 10 week project.
Drilled through sandy gravels and into the weathered strata of the Mercia Mudstone Group, the 7.5m to 9m long nails are simultaneously grout injected along the entire length by a rotary injection adapter.
A combination of hot dip galvanising and epoxy coating was specified to achieve a design life of 120 years.
To complete the works a sprayed concrete covering was applied.