Repairs under way after 15ft hole appears on M2 in Kent
Urgent safety checks and repairs are continuing on a section of motorway where a 15ft-deep (4m) hole opened up in the central reservation.
The M2 in Kent is closed for 10 miles in both directions between junction five at Stockbury and junction six at Faversham. Diversions are in place.
The Highways Agency said the hole was 16ft (5m) by 6ft (2m). It was not yet clear if it is a sinkhole.
The agency hopes to reopen the hard shoulder by 06:00 GMT on Thursday.
A spokesman said geotechnical investigations had continued during Wednesday and the cavity had been filled with about 40 tonnes of pea shingle to help stabilise it.
Kent Police's roads policing unit later tweeted: "There's HOPE of opening one lane both directions tomorrow".
Earlier, video cameras were used to inspect the damage to try to establish how it was caused.
The spokesman said: "Assessment, which is likely to take at least another 48 hours, will be carried out in and around the hole.
"For the safety of road users and road workers, lanes one and two of the motorway will remain closed."
Signed diversions are in place via the A249, the M20, the A20, the A252 and the A251.
Sarah Fray, of the Institution of Structural Engineers, said the cause of the hole was "more likely to be related" to the probable chalk or limestone make-up of the area, along with the rainfall.
She said water had been known to be a "mobilising influence" to cause an underground cavity to collapse.