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MT KEIRA PASS STABILISATION Wollongong City C ouncil. MT KEIRA PASS WORKS About 500m of rockfall hazard reduction works 180m of lower embankment anchoring and no fines concrete reconstruction Around 400m of asphalt and spray seal works 2100m2 of stabilisation, using lime slag. PROBLEMS
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MT KEIRA PASS STABILISATIONWollongong City Council MT KEIRA PASS WORKS About 500m of rockfall hazard reduction works 180m of lower embankment anchoring and no fines concrete reconstruction Around 400m of asphalt and spray seal works 2100m2 of stabilisation, using lime slag
PROBLEMS Ongoing rockfalls, anytime but particularly during heavy rain and storms Continuous slow creep of the road embankment due to fill weathering and settlement Narrow carriageway with poor sight distance increasing the risk to the road user (drivers, walkers and cyclists) MT KEIRA PASS STABILISATIONRockfalls and Embankment Slumping
MT KEIRA PASS STABILISATIONInvestigation Previous slump repairs consisted of repeated layers of deeplift asphalt, up to 650mm thick. Top of guardrail was lower than road crown prior to reconstruction. 20 boreholes were drilled for the design of the embankment works. The pavement was logged and later used in the design of the pavement stabilisation. Note slope of road (Landcruiser) compared to vertical drill rig – 14 degree camber, with radial tension cracking. Geotechnical inspection of cliff face above road for the design and markup of rockfall measures
Upper rockfall hazard reduction works underway, showing meshing, bolting and elevated 38kJ catch fencing installation MT KEIRA PASS STABILISATIONConstruction Lower embankment works occurring concurrently, showing anchoring, meshing and concrete edge reconstruction. Note additional carriageway width (from 5.5m to 7.5m)
Premilling, crossblending and grading to shape – 300mm depth minimum. Grading and compaction of stabilised material into embankment edge. Spreading 5% of 30:70 lime slag binder, water addition and remilling. Final shape was achieved by grading to produce a 2% crossfall to the inside drain and left 30mm low for later AC works. MT KEIRA PASS STABILISATIONStabilisation Works Spray sealed 7/7/2014, getting ready for soft opening. AC scheduled for October.