SH1 SLIP 14 ROCKFALL PROTECTION
Construction of a 2000kJ rockfall attenuator above the state highway on the Kaikoura coast after the 2016 earthquakes
A large slip caused by the 2016 7.8 magnitude Kaikoura Earthquake developed above SH1 south of Kaikoura closing the State Highway.
The head scarp was 200-250m above and nearly twice that long with the lower area of the slip funneled into a narrowed 90m wide chute for rockfall below. After extensive sluicing and scaling to remove the loose debris a 2000kJ rockfall attenuator was designed for installation 30m above SH1 on the newly exposed bedrock in a high risk rockfall zone.
As the crest contained boulders in newly exposed unconsolidated soils, Geovert proposed some light scaling then meshing the entire head scarp with a helicopter to enable safe access for the construction team and equipment to access the rockfall zone safely below. This ensured the best possible program with reduced delays or possible exposure to unsafe conditions. Cranes were used for a majority of the work, set up in lower risk areas off to the sides, reaching in to undertake drilling and construction of the 120m long 4m high attenuator with a 30m long drape to the road.
By taking a safety in construction approach, Geovert ensured the identified risks were managed or removed, allowing the team to build the system in a controlled environment, safely and productively to meet the road opening dates.