Daniels Mill, Bridgnorth, United Kingdom
Steep reinforced soil slopes using Fortrac^® Geogrids

Following slope failure after severe flood events,this sensitive earthworks project was undertakento protect the famous Daniels Mill, and maintainsupport to the viaduct abutment of the adjacenthistoric Severn Valley railway, from furthermovement of the failed slope.

Work commenced on site in October 2009 withthe removal of the failed material from the slopeand the formation of a bermed temporary batter. A basal drainage layer was installed followed bythe construction of a reinforced soil wallcomprising 16 layers of Fortrac® geogrid andsuitable fill to a height in excess of 8 metres. Thefinal slope was graded back from the newreinforced soil wall to a shallower profile some 13 metres above the Mill’s parking area. Despite thecoldest winter for many years, work was finishedin February 2010 with the completion of aWenlock stone wall feature to the lower sectionof reinforced soil wall to match the existingcharacter of this historic Mill.

Project Details
Daniels Mill is a fully working watermill set in theidyllic Shropshire countryside, deep in a woodedsteep valley crossed by the 19th century viaductcarrying the Severn Valley Railway to Bridgnorth.The Mill’s impressive waterwheel has beencarefully restored to its former glory and is thelargest waterwheel powering a corn mill stillworking in England today.

Daniels Mill was hit by the disasters of flooding in2007. Further to these events, a landslip occurredadjacent to the Severn Valley Railway, impactingon the historic mill including damage to the oneof the Mill's outbuildings. The mill is sited in aheritage and conservation area and thereforerequired innovative and sensitive restorationworks.
HUESKER were invited by consultantsGeotechnics Ltd to look at a potential reinforcedsoil solution. HUESKER recommended that thereinforced soil solution be developed further byconsultants PaSCoE, who undertook the detaileddesign of the reinforced soil wall and slope. Closemonitoring and supervision of the work wasundertaken by PaSCoE which allowed changes tothe design and construction to be implementedas the work proceeded following exposure of soiland rock in the slope. This minimised the volumeof excavated soil exported from the site andhence the volume of imported material furtheradding to the sustainability of the solution. Exposure of the viaduct abutment foundationsresulted in changes to the slope profile close tothe abutment to maintain the stability of therailway viaduct.

Over 2000 tonnes of material had to be excavatedfrom the failed slope profile and replaced with astructural granular fill, reinforced with Fortrac^®geogrid and compacted to a high specification.Due to the access constraints, a long reachexcavator was selected for the slope reconstructionwith a tilting bucket attachment. A smallexcavator was used to level the stone in layersand using a tensioning system the Fortracgeogrid was tightened to form the new slopeprofile. This was repeated in layers and includeda topsoil wedge to allow successful vegetationgrowth through hydroseeding. The upper slopewas re-profiled and dressed in a coir matting toprevent short term erosion during the establishmentof the topsoil layer.

Location: Daniels Mill, Bridgnorth, U.K.
Client: Daniels Mill proprietors
Lead Consultant: Geotechnics
Reinforced soilconsultant: Pascoe
Contractor: WM longreach
Year ofConstruction: 2009
Products:
Fortrac^® 110/30-20
Fortrac^® 80/30-20
Fortrac^® 55/30-20
HaTe^® 23.142