Geovert were contracted to the Thiess and McConnell Dowell JV to
undertake the construction of multiple retaining walls for a new
5.5km rail cutting and 2 stations running from Seaford to Noarlunga
in South Australia. Following 4-5 months of ECI, working collaboratively with the JV's design engineer’s Parsons Brinckerhoff, the team optimised the soil nail design using Geovert's detailed quality records from the recently completed ANZAC/South Road underpass to reduce the quantity of soil nailing and therefore improve the JV's program, driving down cost.
The retaining walls were constructed with the installation of soil nails and the placement of shotcrete via a top down method following the joint ventures’ excavation sequence across multiple sites for the 13 structures. At both Seaford and Seaford Meadow stations the shotcrete retaining wall design included complex vertical and inclined concave and convex panels over circa 4,000m² and retained heights in excess of 15m. The shotcrete faces were finished to a stringent U3 steel trowel finish. One of the elements of this stringent specification called for the exposed vertical and inclined retaining wall slabs to achieve a surface finish with a tight tolerance. Despite the painstaking complexities of building to this finish in 3D on a sloping face, as opposed to a flat slab, Geovert constructed and delivered an outstanding project in which the visual eye would assume that precast concrete panels had been placed.
Up to four drilling rigs and several shotcrete and steel fixing crews were used throughout the duration of the project works.