Civil Engineering November 2022 | Vol 30 No 10

14 November 2022 Civil Engineering biodiversity. Independent environ- mental specialists also conducted bi- monthly audits to ensure compliance. Q Q Because of the difficult terrain, the road had deep cuts on one side and steep (near vertical) slopes on the other. The cuts were stabilised with gabion walls (for lower heights) or with a lateral support wall system made of galvanised steel soil nails grouted into the banks to depths ranging from 6 m to 10 m. The system was completed with shotcrete applied over galvanised mesh. Controlling groundwater seepage in the cuttings was a challenge. Using this system, approximately 14 200 m² of cuts were stabilised, some of them reaching heights of 10 m above road level. This work was completed by specialised subcontractors. Q Q Detailed design of the lateral supports took place during construction be- cause of the highly variable geological conditions and limited geotechnical investigations during the design phase. In some restricted cut zones, the lateral support had to be placed further into the cutting to create an earthen platform for the drilling rig to install soil nails on the upper regions of the cutting while still keeping the road wide enough for passing traffic. Q Q The incorporation of recesses and “baskets” into the shotcrete walls in- novatively allowed for the planting of selected indigenous flora and improved the aesthetic appearance of the walls, which were also stained to give them a more natural look. Q Q Shotcrete was used sparingly to expose the more competent and durable sand- stone cut faces, which were sometimes stabilised with rock bolts. Q Q Approximately 11 000 m³ of gabion baskets were built, primarily to sup- port the steeply sloping fill banks. Q Q All of the gravel for the upper road layers came from a borrow pit and quarry located a long distance from the site. Crushing, screening, and hauling to the site were all part of the operations. Haulage was particularly challenging due to extremely muddy conditions during the summer rainfall period. A bitumen-stabilised base was used to allow traffic to travel on the completed layer immediately after construction. Q Q Local labour and SMMEs were exten- sively used during the construction of the concrete side drains, culverts, and concrete barrier walls. Q Q Special care was taken to ensure that the road’s alignment was optimised at places like Yellowwood Corner, where a scenic boulder formation and old yellowwood trees had to be carefully avoided. Before construction began in other sensitive areas, such as wetlands and near waterfalls, intensive discus- sions were held between the contractor, supervision staff, environmental con- sultant, and various other experts. Q Q Another challenge was constructing a switchback section – known locally as “Nip and Tuck” – with continuously reinforced concrete pavement. For this section, various concrete finish options were carefully evaluated, which would then aid in decisions for future upper section options. This included research into the effects of pigmenting the concrete surfacing to raise surface temperatures, reducing the risk of ice formation on the road surface during the winter months. For this switchback section, gabion and Terramesh® retaining walls up to 7 m high were built. Q Q The project’s landscape architect recommended that the ruins of the old Good Hope Trading Station be cleaned up and developed as a tourist attraction. Trading posts were set up in the early days when goods were transported between South Africa and Lesotho by mules, horses, and donkeys. Q Q For improved aesthetics, the concrete barrier walls were stained and given a “stacked stone” formed finish. Small access “hedgehog holes” were also incorporated at various points along the barrier wall to help small creatures cross the new road. Q Q Prior to clearing the site, specific plants, trees, and sods were carefully removed for temporary storage and then replanted when road verge reha- bilitation began. Sods of indigenous grasses were replanted, and larger areas were hydro-seeded with a seed mix derived from the local grasses. Ultimately, innovative designs met the cli- ent’s requirements while also addressing the problematic mountainous terrain and environmental constraints. Special care was taken to minimise the visual impact on the environment. Concrete faces were either lined with form liners to provide a stone-packed wall finish or shaped to mimic rock formations and pigmented to match the natural stone. CONCLUSION The Phase 2 Roadworks Project was suc- cessfully completed within the revised budget and timeframe. It also achieved the targets for employing local labourers and SMME contractors. The original contract value was exceeded, owing primarily to extreme physical and climatic conditions, as well as the effects of the Covid-19 pandemic. However, the necessary financial pro- cesses and procedures were consistently followed, including interactions with, and approvals from, the Provincial Treasury. This is a proud project that will enable more tourists to experience the beauty and wonder of the uKhahlamba Drakensberg Park World Heritage Site. It has set the benchmark for the next phase of construction, which will complete the route to the Sani Top.  Approximately 11 000 m³ of gabion baskets were built