Work on a £1M package of stabilisation around Undercliff Drive on the Isle of Wight, which started in winter last year, will not restart until ground movement stops according to a new report.
The Isle of Wight Council published a report by its PFI roads organisation Island Roads yesterday which said that it is looking to construct a temporary access road for residents but the affected road will remain closed for the foreseeable future.
Assessment of the failure, which was first recorded in February, has been shown by Ramboll to be as a result of both shallow ground movement and rotational failure. Inclinometers installed as part of the November 2013 stabilisation work show movement started in January 2014 at 14 to 15m depth, which is still continuing with around 10mm of incremental movement a week.
According to Ramboll, previous monitoring of the landslide complex shows that the increased ground movement this year is as a result of heavy rain and has not been activated as a result of the Island Road’s stabilisation work last year.
The report concludes that the current ground anchor solution is no longer suitable and that significant fill would be required to raise the road back to an acceptable alignment. Environmental restrictions prevented plans for groundwater control work during the November 2013 scheme which could have minimised the current problems.
There are six repair options proposed by Ramboll including re-establishing pedestrian access on its own, repairing and reopening the road in one direction, repairing and reopening the road in both directions, establishing a new route to the effected properties, constructing a temporary vehicle access route and permanent road closure. The cost to deliver these plans range between £100,000 and £20M.
The council has said that it intends to consult with property owners and obtain final prices, as well as waiting until ground movement stops, before making a decision.