VAN ELLE recently finished a contract to stabilise a cable and winch powered haulway at a hydro-electric power station on the Isle of Skye in Scotland.
The foundation contractor was working for client and owner/operator Scottish and Southern Energy. It designed and installed the ground anchors to stabilise the ground around the railway which carries personnel and materials down an escarpment to the Storr Loch Power station overlooking the Sound of Raasay, 16km north of Portree on the east coast of the island. The anchors also provide support to the railway's concrete footing.
Work was carried out on the steepest part of the slope next to the two 1m diameter pipelines supplying water from the dam built at the end of Loch Leathan to the power station.Engineer was the Babtie Group.
Work was carried out from the haulway car, which had been partially dismantled to provide a flat open working platform. Following an anchor load test, the 7.1m long 30/16 Ischbeck Titan anchors with working loads of 50kN were installed using a top-driven hammer and drill fitted to a 3t mini excavator.
The heads of the anchors had to be set below the level of the railway footing.Each was pre-cored so the bearing plates and nut assembly could be countersunk below the finished surface of the railway slab. Grouting was carried out during drilling to produce a grout body along the full length of the anchor.
A series of hand-augured investigation boreholes were sunk during the contract to verify ground conditions. Standpipes were installed to monitor groundwater movement.
Trial holes were also put down to verify foundation depths and ground conditions around the pipelines.
Finally, a series of drain holes were installed along the length of the treated area.