Road fix decision in May
A decision on the best option for fixing the crater sized SH25A slip will be revealed in May, Waka Kotahi says.
Yesterday was given a firsthand look at site of the broken arterial route in Thames-Coromandel district.
The 12km drive inland to the site of the slip revealed a windy route past mounds of dirt, fallen debris lining the roadside and crumbled cliff faces with trickling streams cascading down, a reminder of the deluge that swept away the peninsula’s main road last month.
Contractors have been carrying out ‘‘geotechnical investigations’’ to decipher which of the three proposed options pitched for fixing the highway will be most suitable, all while a 9-12 month timeframe set by the agency, looms.
A bypassing road, a bridge or a freshly built road were the options being looked at.
The SH25A slip began with cracks in the road after Cyclone Hale in early January before worsening during a ‘‘long, wet, tough summer’’ with consecutive storms, including Cyclone Gabrielle in February.
It had now expanded to a mammoth 130m wide and 30m deep.
With winter approaching, the threat of further rain and damp conditions was not far from the minds of those racing against the clock to restore access across the roading network in the Coromandel region.
The site of the slip was still ‘‘very weak’’ and if exposed would be susceptible to further damage by future weather events.
Regional Manager of Infrastructure Delivery (Waikato/BOP) at Waka Kotahi, Jo Wilton, said there was no certainty when it came to the cost of the gigantic repair job.
It would depend on which option would ‘‘work best’’ while taking into consideration, design, cost and the time it would take to build given contractors wanted a solution that could ‘‘be done fast’’.
‘‘The scale of this project for a slip is really substantial, the slip is bigger than a rugby field,’’ Wilton said. ‘‘We’re looking at having a decision in May.’’
The proof was in the pudding which in the case of SH25A was the soil and rock foundations.
Lead geotech engineer from BECA Nathan McKenzie said they were about two thirds of the way through geotech investigations which were expected to be complete this week.
Waka Kotahi alongside Higgins Contractors, and seismic experts from Perry Geotech and Pro-Drill, had been drilling multiple 50ml boreholes which drove around 20 metres into the ground.
This was to test the contents to find the most ‘‘stable and strong soil or rock’’ which would be able to hold the weight of a new structure without collapsing.
Thames-Coromandel District Mayor, Len Salt said it would be a relief for the people of the Coromandel to have certainty about the best option for fixing the broken road.