A46 road closure - South of Painswick

Photo of drilling rig

UPDATE: The road will reopen under traffic lights at approximately 4am Thursday 18 April, after the completion of overnight works. Information about future works will be published on this web page when further updates are available.

A road closure was in place on the A46 at the Pincot Lane / Wragg Castle Lane junction, approximately 2.5km south of Painswick.

On 7 March 2024 a hole was found beneath the road and temporary traffic lights were installed. Technical inspections were carried out and on 11 March and the road was closed for safety reasons as cracks have also been found at this location.

Using different investigation methods we have so far been able to determine that there do not appear to be any further significant voids, but that the ground is cracking significantly below the East carriageway towards Stroud. This cracking, the voiding, and the slight deformation of the embankment between the A46 and Pincot Lane suggests that the ground is moving and in need of stabilisation. Until investigation is complete we cannot determine when the road can be made safe to reopen.

The excavations are continuing 18-22 March to further investigate the ground conditions at a deeper level but also to find the exact location of the utility services located within the carriageway, such as gas, water and communications cables.

The diversion route is signposted. The route is designed to be suitable for larger vehicles that would have used the A46. Please note that smaller lanes near the road closure can not accommodate diverted traffic, so we recommend all drivers use the signposted diversion route.

We will continue to monitor the situation using data from equipment installed under the road.
We expect to return during the summer when the drier conditions are more favourable for inspection of the culvert and adjacent fields.
A road closure will be required to complete this work and notice will be provided.
Updates will be published on this web page and on social media when further information is available.

Ground investigation works completed.
Equipment removed from site.
Road open with traffic lights from approximately 4am Thursday 18 April.

Ground Investigation (GI) is progressing reasonably well on site, with the last borehole currently being drilled in the carriageway. Re-grouting to fill the holes will then be undertaken to complete this activity towards the end of this week or beginning of next. Unfortunately, we have had to cancel the boreholes planned for the field locations either side of the A46 due to the ongoing rainfall - the ground conditions are too wet and unsafe for the equipment. The need to return to install these will be assessed later following taking readings from the installed equipment which will show any ground movement and determine the need for further locations to gather additional information.
All de-watering equipment is being decommissioned and removed from site, again with the view to returning during the drier summer months to further investigate and undertake any required repairs to the culvert under the A46 and Pincot Lane.

Trial holes completed and Ground Investigation started on site. This is a process of drilling boreholes (using the drilling rig pictured below) into the ground and installing ground monitoring equipment. The ground monitoring equipment will allow us to closely monitor any ground movement going forwards, with minimal disruption to the public, and it will aid the design of any repairs to be undertaken to stabilise the embankment and road.
Drainage of the water from the flooded field to the West of the A46 was undertaken but unfortunately this only uncovered 500mm+ of silt meaning that the culvert below the road could not be located and is very likely almost completely blocked. This investigation will need to be put on hold for now and will recommence during the summer. A temporary road closure will be required during the summer due to the size of the water pump and other plant required for the operation and will of course be advertised in advance.

Trial trench investigations continue to establish utility service locations (see photo below). Severn Trent Water have also visited the site to confirm the water main location. This information is required to ensure that we do not disturb the service during Ground Investigation drilling planned to start 2 April.
Gloucestershire County Council engaged a Ground Investigation contractor to start works on 2 April for 2 weeks. This will involve drilling boreholes at a number of locations on the A46 and surrounding fields to determine the ground conditions and depths of failures causing the landslip and cracking on the road.
A specialist contractor was consulted with regards to pumping of water flooding the field to the west of the A46. The equipment has now arrived on site and the drainage will take place Wed 27 – Fri 29. This may cause some short delays to traffic using Pincot Lane as the water will need to be pumped through pipes over this road to reach the watercourse below. If the area can be de-watered successfully this will provide the best chance for inspection of the culvert under the A46 to establish whether there is any collapse or defects causing the voiding. The de-watering will also relieve the pressure being applied to the already saturated embankment.
Additional signage confirms “Businesses open as usual” to support businesses along the route into Painswick. “Unsuitable for diverted traffic” signs have also been installed on the minor roads to deter vehicles using these rather than the official diversion route.

This week we continue to dig trial trenches to examine the carriageway below the surface. Significant cracks have been found, as pictured. We are also investigating the options for removing standing water that has accumulated in the field to the west of the A46 and is saturating the embankment on which the A46 stands.

Survey crews arrived on site to determine the condition of the drainage system and investigate the extent of a holes beneath the road. This week we also started to dig trail trenches to examine the condition of the road beneath the surface. The picture below shows evidence of cracking and movement within the edge of the carriageway: