Geotechnical investigation including:
- Deep inclined cored boreholes,
- Test pits and bedrock strength testing,
- Landslide stabilisation
- Reconfiguration of a section of coastal path.
Severe storms in June 2016 had resulted in a landslide affecting an old fill batter slope formed to infill a gully in the cliff line on the cemetery’s eastern boundary. The coastal path’s iconic nature meant the project team, in collaboration with Council, had to develop an aesthetically pleasing solution to the significant geotechnical, coastal and structural engineering challenges.
A robust seawall was required to protect the bottom of the slope from erosion. The steep slope and deep gully posed significant design constraints. The design also needed to control the stormwater collected from the landward side of the hill with the cemetery grounds.
JK Geotechnics completed slope stability analyses to inform the overall design. Permanent support for the cemetery’s original sandstone wall required new piled wall. The upper slope was benched to provide public access and provide the opportunity to form new hanging swamps. A new viewing platform at the crest of the slope was constructed and a new a 5m-high concrete seawall was installed to protect the bottom of the slope. The seawall base had to be strong enough to form a bridge over the a weak, deeply weathered igneous dyke intrusion into sandstone bedrock. Stormwater was collected and piped down to the seawall for disposal. The project was successfully completed and the path reopened to the public in November 2018.