Case Study: M50 Southern Cross Route Rock Slope Stabilisation
Client: National Roads Authority
Main Contractor: BAM Contractors
Contract Period: 2001
Bam Contractors was main contractor for the Southern Cross section of Dublin’s M50 motorway which included a 1,000m long rock cut with slope heights varying from 3m to 25m. Upon completion of the rock excavation, the geology exposed in the weathered granite slopes highlighted the need for considerable stabilisation work.
BAM Ritchies was contracted by BAM Contractors to carry out the following elements:
- scaling 9,000m2 of rock slope to remove loose and ‘hung up’ rock
- installation of 190 rock anchors to stabilise major joint patterns within the rock slope
- rock bolting to restrain small blocks
- installation of 6,900m2 of rock fall mesh to control any future rock fall
BAM Ritchies used a telehandler mounted drilling rig to reach locations up to 10m above ground level and a crane mounted drilling basket to access locations up to 20m above ground level. Both machines used down-thehole drilling equipment with air flush. Production rates of five 15m depth holes per day were achieved.
Access for the scaling and rock fall netting work was provided using a combination of mobile elevating work platforms and rope access techniques.