Phoenix Sewer Pumpstation

Mukona Consulting Engineers (Pty) Ltd was appointed by INGEROP South Africa (Pty) Ltd to conduct a geotechnical investigation for the proposed upgrade of the sewer network and pump station in Phoenix, Milnerton.

The project site is located within the City of Cape Town, approximately 9.2 km from Cape Town’s Central Business District.

The investigation was undertaken to assess the underlying soil and groundwater conditions and identify geotechnical factors that could influence the design and construction of the proposed infrastructure. The findings provided essential information for foundation design, excavations, earthworks and the installation of underground sewer services, helping the project team manage ground-related risks and develop safe, practical and cost-effective engineering solutions.

Scope of Work

Desktop study to adequately review all available information (topographic, geological, hydrogeological, seismic hazard maps, NGA).
Geophysical survey: Ground penetration Radar and Multichannel Analysis of Surface Waves (MASW), to determine the shear-wave velocity against the subsurface profile.
Excavation, profiling and sampling of test pits
Rotary core drilling to a maximum depth of 8m below ground level to determine the subsoil conditions.
Dynamic cone penetrometer was conducted to determine the consistency (in-situ density) of the subsoils below the footprint of the proposed sewer line.
Dynamic probe super heavy was typically used to obtain a continuous profile of the consistency (strength) of the subsoils with depth.
The fieldwork was supplemented with soil laboratory tests on representative samples of the materials encountered below the site.
The site features a mantle of asphalt, fill, and transported soils (dune sands) down to at least 15 meters below ground level.
The transported soils consist primarily of silty and clayey sand, generally medium dense up to 3.5 meters, with localized loose sand pockets.
Standard Penetration Test (SPT) results show very dense to hard soil lenses within the transported soil at 1.5-meter intervals in boreholes.
Groundwater levels were found at depths of approximately 2.0 to 2.90 meters near the pump station and 0.25 to 1.0 meters along the sewer line, indicating the presence of perched and shallow groundwater levels.
Transported soils classify as Poorly graded SAND CLAY (SP), silty SAND (SM), and Well-graded SANDS-silty SAND (SW-SM) per the Unified Soil Classification System (USCS).

Phoenix Sewer Pumpstation

Mukona Consulting Engineers (Pty) Ltd was appointed by INGEROP South Africa (Pty) Ltd to conduct a geotechnical investigation for the proposed upgrade of the sewer network and pump station in Phoenix, Milnerton.

Scope of Work

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