Civil Engineering April 2022 | Vol 30 No 3

oN THE COVER T he site is located in a prime location within the Cape Town Waterfront, off Dock Road, where Keller Geotechnics SA has completed a number of successful and challenging projects. PROJECT SCOPE Keller Geotechnics SA’s project scope entailed the construction of a three-level basement with a depth up to 10 m, explains Contracts Manager Daryn Cloete. The client and developer, V&A Waterfront Holdings, awarded the contract in July 2021 and the project was completed in December 2021. The project included rock breaking, carting away and the construction of the lateral support works. The basement comprised 2 844 m² of lateral support and approximately 52 900 m 3 of earthworks. A section of the basement wall was shared with the neighbouring property basement, requiring this existing wall be underpinned. NOT WITHOUT CHALLENGES Cloete explains that the sequence of the works, with removal and relocation of services, meant that plant was required at different periods of the contract as and when the programme dic- tated. Unknown live services running through the site meant the sequencing of works was changed frequently to quickly suit the reloca- tion process and maintain continuity of works. Below the clayey silt sand, which was ap- proximately 1.5 m below ground level, was the Malmesbury bedrock, which turned out to be slightly weathered to unweathered hard to very hard rock. A total of 52 900 m³ of material, mostly hard rock, was removed from the site. Breaking the 70 MPa rock on site made it dif- ficult to stick to earthworks production targets. Despite the numerous challenges, the six-month project – which commenced on 29 June 2021 – was completed on time and within budget. A big factor contributing to the success of the project was the way in which the Keller Successful Keller basement project supports new V&A development Keller Geotechnics SA recently called on its experience to prevail over an array of challenges to deliver a 10 m deep three-level basement at the V&A Waterfront Parcel M site in Cape Town. 4 April 2022 Civil Engineering Installing soil nails Installing the last rock bolts