MHB recently carried out design works for the Phase 7,8 and 9 rock catch basins at the Rest and Be Thankful –A83 Trunk Road. The basins were formed along the A83 to catch rock boulders / soil debris during landslide events and prevent them from reaching the trunk road. Formed in natural rock the basins have a typical rock face height of 15m, plan dimension 2-10m and total length of all 3 basins 150m.
MHB Consultants were responsible for all earthworks design under this Contract. Our design included design of the excavated faces in rock and also comprised included strengthened earthworks with TeccoMesh and anchors for soil slopes. We employed an observational approach in relation to the rock cut stability within the basins. This involved high level coordination and liaison with Geo -Rope during rock excavation the rock faces were mapped and analysed as construction proceeded to minimise the amount of rock reinforcement required.
All rock spoil was re-used 4 miles north of the site at Glen Kinglas to create rock bunds to protect the A83 from soil landslides known to occur in that area. MHB also undertook the earthwork design for these bunds.
As part of the works we also carried out the design of drainage improvement works at both the main basin sites as well as the spoil disposal area at Glen Kinglas.
Phases 7,8 and 9 construction works were undertaken while the Trunk Road was kept open for traffic and under a traffic management system consists of one lane closure.
Works were completed by Geo-rope, the Principal Contractor, in 2019.
Photos courtesy of MHB, Geo-rope and BEAR Scotland.
Video courtesy of CECA Scotland as part of a submission to the Civil Engineering Awards 2019.