Netting and dowelling has been installed on the mound on which Edinburgh Castle rests, to prevent rock plunging onto road and railway lines below.
Edinburgh Castle is instantly recognisable as a Scottish landmark and dominates Edinburgh’s city centre.
The castle is surrounded by large volumes of daily traffic with footpaths around the castle’s perimeter, road traffic to the south and Edinburgh’s main railway line to the north west.
The mound on which the castle stands is prone to rock falls due to natural weathering which affects the basaltic plug from which it is formed. As a result, it requires rock stabilisation to ensure the local area, including Princes Street Gardens footpath and the nearby railway lines, remains clear of rock falls.
Trac Engineering carried out work to install 15 rock dowels into the northern flanks of the Edinburgh Castle rock face.
Due to the proximity of the railway lines, it was also deemed necessary to install netting to the rock face to minimise the impact of rock fall during the pinning works.
The initial plan was to remove the netting after the work was complete, but this decision was reversed as it was decided that the netting would provide additional rock fall protection.
The contractor installed the rock dowels under direction from Historic Scotland, consultant WA Fairhurst and Network Rail, which had representatives present during the operation.
Rock fall protection netting was installed using Trac’s mesh handler − mounted on a Merlo 40.25 rig − and manual haul lines, enabling the netting to be draped into position without significantly disturbing the rock mass.
Once secured, the installation of rock dowels using rope access techniques could be undertaken through the netting, minimising the rock fall potential.