Civil Engineering April 2021 | Vol 29 No 3

basement against large scale water ingress. It was an important factor in the design of the project.” “Apart from the basement final level being below mean sea level, the Keller site team also had to contend with substantial groundwater in the excavations, which re- quired dewatering. This water was pumped and filtered prior to removing it from site,” Daryn continues. Despite the Covid-19 lockdown set- ting the project back by three months, as well as the service relocations and additional works, Keller was able to meet the prescribed six-month construction programme, handing over the project in September 2020. OTHER ASPECTS OF THE PROJECT The challenges of sequencing the earth- works, with all its obstructions, changes in rock, and dewatering, highlighted the importance of the jet grouting in sealing off the basement to strong underground water flows from both the ocean and mountain side of the site, explains Daryn. The Keller arsenal of equipment, local network, and team effort on site with profes- sionals, client, main and subcontractors, al- lowed for changes to scope and programme to be accommodated without incurring further programme drag. Additionally, the rock level on one section of the project site was much deeper than envisaged, and Keller had to install large diameter temporary cased auger piles for the foundations. Daryn says the major talking point for Keller on this large project was the ability to keep up with the programme in the face of the Covid-19 pandemic and an array of unforeseen challenges. “We had to do partial handovers to the building contractor to allow them access to the foundation piles and other portions of the basement while we were still busy on site. This was another challenging, yet well executed and flagship project for Keller.” As Henry Ford said, “If everyone is moving forward together, then success takes care of itself” and that is what Keller, along with the client, professional team and subcontractors, achieved on this project. For more information contact Anton Stoll +27 (0)21 797 0525 anton.stoll@keller.com Keller Geotechnics SA Civil Engineering April 2021 5 Gearing up for the auger piles installation Works well under way Completed works on final level