Source: New Zealand Transport Agency
Thick fog delayed work starting at the SH8 Cromwell slip site until around 11 am today, says Waka Kotahi NZ Transport Agency.
The slip above State Highway 8, near the intersection with SH8B, Deadman’s Point bridge, began to move a week ago with traffic reduced to a single lane.
On Friday shipping containers were placed along the base of the slip, allowing two-way traffic to resume, with speed restrictions, says Waka Kotahi Maintenance Contract Manager Mark Stewart.
The (estimated) 9000 cubic metre slip was sluiced last week using two helicopters, removing loose material and enabling geotechnical advisors to get a closer look at the underlying material.
“Over the weekend we continued to monitor the slip closely and there was between 20 and 30cm movement at different points on the site,” says Mr Stewart.
“We have now started deconstructing the slip on both the north and south sides. On the north side an excavator is completing track cutting and preparatory work to gain access to the northern edge of the slip. From there it will remove some of the larger rocky material at the top and reduce the weight above the lower slope.
“On the south side, abseilers have been placing airbags in established cracks and unstable rocks are now being dislodged.”
Mr Stewart says the work will continue for several more weeks so road users should continue to build in an extra ten to 20 minutes just in case traffic is temporarily stopped while rocks are safely being dislodged.
“The slip is moving at different rates in different locations, and the scale and complexity means it will take some time to safely stabilise the site.
“We are constantly monitoring the slip to ensure that the road remains safe for people to use.”
State Highway 8 is the main link between Alexandra and Cromwell, through the Cromwell Gorge, with no convenient detour route.
Read these earlier Waka Kotahi media releases for background and photos of this unstable schist slope:
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