Highways England (HE) has confirmed that it is hoping to reopen one lane on the northbound A249 later this week, following completion of temporary works.
They have confirmed that it is "currently unsafe to reopen the slip road and inside lane as surveys have not confirmed the stability of the ground underneath the road and the adjacent void in the ground is a potential risk to drivers".
Timeline of work carried out so far
- From Monday 11th to Friday 15th January, Southern Water installed a replacement water main under the A249
- On Friday 15th January, the old water main was depressurised and as a consequence, a void started to appear.
- Surveys could not be carried out until the level had receded. Pumping the water out could have made the void worse.
- An initial pavement condition survey was carried out on the night of Friday 15th January to determine the extent of the void under the northbound carriageway.
- A second survey was carried out this Monday (25th January) to determine the ground stability underneath lane 2 to ensure that it is safe to reopen.
- While waiting for the technical teams to analyse the results, plans have been underway to explore other options to manage traffic.
- Work is now ongoing to fill the void with concrete. HE anticipate that this work will be completed by tomorrow (Thursday 28th January) and this sgould then enable HE to re-open one lane of the northbound carriageway.
Why is it taking so long?
A team of Highways England specialist geotechnical and pavement engineers, and specialist contractors, have been carrying out surveys of the integrity of the carriageway to see if it is safe for traffic to use. These surveys are used to determine the physical properties of the ground underneath the road surface. They are carried out using a combination of non-invasive techniques, similar to an x-ray of the road and taking core earth samples. The results of these surveys will be analysed by a team of specialist engineers to build a profile of the ground conditions. Further surveys will be carried out over the next couple of weeks by specialist engineers to help HE to determine the scope and extent of the full repairs.