A 3m deep, 6.5m diameter hole has opened up underneath the northbound carriageway on the A1 near Newcastle.
Highways England said that it is currently carrying out urgent repair work to fill in the hole which appeared under the carriageway and is believed to be related to old mine workings in the area.
The body said that work had been ongoing overnight and throughout the day to investigate the extent of the hole, and it had started the necessary repairs to make the carriageway safe for traffic.
“Safety is our top priority; we have to ensure the carriageway is totally safe before drivers use it,” said Highways England duty operations manager Rob Beckitt.
“We and our contractors have been working hard with partners since the hole was discovered…and will continue to do so to make the carriageway safe as quickly as possible.”
The large hole was discovered by Highways England on Saturday night (25 June) when a slight dip in the road surface became apparent. It said that workers then cut around the dip to investigate and discovered a large void underneath the road surface. There was no traffic using the section at the time as it was in an area that was cordoned off due to roadworks elsewhere on the A1.
The hole, estimated to measure around 140m3, is being filled with a specialist concrete mixture before the road is resurfaced. Highways England said that contractors would subsequently need to drill holes to pump more material underneath the repaired area to prevent a repeat collapse.
The road is expected to be safe to reopen on Wednesday morning (29 June).