N2 Umgeni Interchange Geotech. Investigation

N2 UMGENI INTERCHANGE GEOTECHNICAL INVESTIGATION: 
A Commitment to Community and Excellence

The geotechnical investigation for the N2 Umgeni Interchange to south of the Mount Edgecombe interchange was a comprehensive undertaking, encompassing a significant scope of work. The project involved the completion of 228 boreholes, totalling an impressive 4709 metres drilled using six rigs. Complementing this extensive drilling programme were 98 CPTu tests (480 metres), 12 DPSH tests, 81 hand-dug test pits (to 1.5 metres), 115 slots excavated with an 8-ton mini excavator, and 213 DPL tests.

This project marked a significant milestone for GeoGroup as their first contract with a crucial requirement: to allocate 30% of their costs to local, upcoming businesses. Demonstrating a deep commitment to community growth, which is an ethos central to GeoGroup's values, the project team collaborated with the Project Liaison Committee which exceeded this target by reinvesting an impressive 42% of the contract value into the local economy. This investment spanned various essential services, including staff accommodation, security, traffic accommodation, plant for access creation, toilet supply, staff transport, and diesel supply, fostering tangible economic benefits within the working community.

Beyond direct investment, the project also prioritised local employment. Twenty-one temporary workers from the area were employed to support both the technical teams and the geologist. This initiative provided these individuals with invaluable on-the-job experience, fostering teamwork and collaboration skills within a large-scale project environment – skills that will undoubtedly enhance their future employment prospects.
The successful execution of this extensive investigation was not without its challenges:

• The sheer volume of traffic on this critical stretch of the N2 required the employment of additional traffic accommodation personnel to ensure the safety of both the public and the project team, effectively mitigating the high risk of accidents.
• An exceptionally wet season presented a significant threat, with near loss of drilling rigs on two occasions due to rising floodwaters. Proactive risk management, including nightly relocation of rigs to higher ground, proved crucial in safeguarding valuable equipment.
• The presence of main fibre optic lines adjacent to the road necessitated meticulous excavation of every investigation point to a depth of 1.5 metres to confirm the absence of underground services, adding a layer of complexity and time to the process.
• Difficult terrain, including very steep slopes, required innovative solutions to position drilling rigs. Collaboration with private landowners allowed access to properties, enabling rig placement over fence lines, with the construction of sandbag platforms to ensure stability.
• Twelve of the drilling locations next to the Prasa rail line demanded constant communication and co-ordination with Prasa representatives to secure timely access permits, a critical factor in adhering to the project timeline.
• Regular and thorough monthly safety audits conducted by the client representatives emphasised the continuous focus and meticulous attention required for the project's safety file system.

Despite an initial contract period of seven months, the project was successfully completed within 8.5 months, a testament to the team's adaptability and resilience in the face of the extended rainy season and the need for additional investigation slots. Remarkably, all drilling activities were finalised on the very last day of the adjusted contract period.

The N2 Umgeni Interchange geotechnical investigation stands as a testament to GeoGroup's commitment to not only delivering high-quality technical work but also to fostering meaningful community engagement and demonstrating exceptional problem-solving skills in the face of significant logistical and environmental challenges. The project's success, marked by exceeding local investment targets and navigating complex site conditions, highlights GeoGroup's dedication to excellence and responsible project execution.