en.Wedoany.com Reported - Bear Scotland plans to carry out embankment stabilization works on the A83 between Loch Restil and Butterbridge in Argyll and Bute, an area north of the landslide-prone "Rest and Be Thankful" section.
Commissioned by Transport Scotland, Bear Scotland will commence embankment stabilization construction on two sections of the A83 on July 13. The work will be carried out by its strategic projects team, with scheme design completed on behalf of Jacobs. The two construction sites are adjacent, located near Loch Restil and Butterbridge respectively.
At the Loch Restil site, geotechnical walkover surveys identified two areas of scour causing internal instability within the embankment, leading to the decision to proceed with the works. A Bear Scotland representative explained that the scour resulted from water erosion in watercourses adjacent to the embankment. At the Butterbridge site, slippage of the embankment occurred, causing the foundation of the safety barrier to be undermined. The spokesperson added that steep slopes and surface water runoff from the hillside may be contributing factors.
The instability on this section of the A83 is primarily attributed to the local superficial geology, consisting of glacial till and alluvial deposits. The spokesperson noted that these deposits may contain poorly sorted sediments and clay materials, making them susceptible to the variable weather patterns in the Argyll region.
At Loch Restil, the stabilization solution will involve using rock bags to construct a new riverbank revetment. Rock bags are made from synthetic fiber mesh bags filled with single-sized or narrowly graded rock. At Butterbridge, construction will begin with excavating and benching the embankment, followed by the installation of geotextile fabric, and finally backfilling with 6F2 fill material. The embankment will also be widened to provide sufficient offset for the replacement safety barrier.
Bear Scotland stated that all works are dependent on weather and embankment conditions, the latter of which may only be fully understood once investigations commence. The works are currently expected to be completed by September 14.
Michael Baxter, Bear Scotland's North West Improvement Project Manager, noted that these embankment stabilization works are critical for the continued safe operation of the A83. The works have been planned to minimize disruption to road users as much as possible, with two-way traffic lights operating 24/7 and a temporary 30 mph speed limit, though delays are expected during peak hours.
The most problematic section of the A83 trunk road is its highest point, "Rest and Be Thankful." Following a major landslide in 2020, Transport Scotland has been developing a long-term mitigation solution involving a 1.4-kilometer-long debris flow shelter, alongside a medium-term plan to construct a more resilient diversion route on the Old Military Road. The latest update in October last year indicated that geological survey work for the long-term solution had been completed.
