Gloucestershire County Council has said that unexpected issues with utilities, combined with poorer than expected ground conditions, will result delays to slope stabilisation at Horsley Hill.
The work to stabilise the slope, which first failed in 2013, was expected to take 15 weeks but the deadline for completion has been pushed back by a further five weeks.
Funding for the £550,000 scheme was approved late last year and involves excavating 2m below the road surface to bedrock and installing 94 pre-cast concrete anchored L-sections to support the new road. The road is closed while the remediation is underway and a 17.5km detour is in place for road users.
Speaking to local media, the council’s contracts manager Mark Darlow-Joy said: “When carrying out these much needed improvement works, crews came across some unavoidable setbacks.
“These include a two week delay due to Severn Trent Water works, a further two week delay because of unexpected BT services and a one week set back caused by multiple holes, some up to 21 feet deep.
“Unfortunately due to these reasons, and the ground being in worse condition than expected, it is still very unsafe and will have to remain closed for up to an additional five weeks.
“We would like to apologise for this inconvenience and reassure people that we’re working with contractors to get the work completed as quickly as possible.”