RITCHIES, EDMUND Nuttall's geotechnical division, is in the middle of slope stabilisation work for Network Rail on a railway cutting at Preston Brook near Runcorn in Cheshire.
Main contractor on the job is the North West Structures Alliance, a partnership between Network Rail and Edmund Nuttall.
The £1M scheme involves installation of about 1,860 self-drilling soil nails, making for a total length of about 20km.
Works began with slope devegetation and reprofi ling, including the cutting down and stump removal of about 70 trees.
The Dywidag R32N MAI bars, between 10m and 12m long, were installed by Hydraulic Klemm hammers running on feed beams mounted on long reach excavators.
Each nail uses a 100mm diameter sacrifi cial hardened clay bit with the top 3-4m galvanised and is finished with a 300mm by 300mm flat galvanised bearing plate.
In March, site workers began installing the bottom row of nails - close to the track and overhead line equipment - using one of Ritchies' bespoke rope-supported Terrapin rigs, which uses a compressed air powered rotary head.
About 10,000m 2 of Maccaferri MacMat-R will cover the slope, with another 9,000m 2 of jute ensuring soil retention and vegetation propagation in certain areas.
Soil removed during reprofiling will be spread back over the jute and MacMat-R before the slope is hydroseeded to restore vegetation.
Work started in March and is due to finish in June.