A 300t rock precariously positioned over the busy “Rest and Be Thankful” A83 road in Scotland.
The area is renown for debris flows. Controlled removal or blasting of the bolder would risk triggering more debris flows and slope instability.
Project designers were Waterman who designed the solution along with specialist contractor Georope and Linear Composites, for client BEAR Scotland. The restraint system for the rock consisted of seven Parafil tendons which were passed through holes cored through the boulder, and terminated.
The Parafil tendons were then attached to secure anchorages upslope of the boulder. Parafil Type F synthetic tendons are made from Kevlar fibres, encased in a super-tough sheathing. They provide a high strength and low weight restraint system, far superior to any high strength steel solution.
The added advantage is that being corrosion-free, the tendons would provide a long design life in this mountainous environment. Linear Composites is Maccaferri’s specialist geosynthetic manufacturing division.
Clients will be more familiar with Maccaferri’s Paralink, Paragrid and Paradrain geogrids, so this is a nice opportunity to showcase other geocomposite products within the Maccaferri and Linear Composites portfolio.