N2 Section 19
& R61 
Port St Johns

R391 million

Client: SANRAL

Project Description

Emergency Slope Repairs

This project is located in the Eastern Cape Province, on National Rote N2 Section 19 and the R61, near Port St Johns. The expected project duration is 16 months.

The necessity for the project arose due to severe stormwater damage to the existing road in four separate locations, with the construction of two separate alternative routes to get around the damaged sections required.

Each site has different remediation measures proposed.

Site 1 – Xesi N2 Section Section 19 km 57.4

The road has suffered severe washaways in this location with geotechnical slope stability measures introduced.

  • The existing fill material is to be removed and stockpiled in 6 meter high benches, 24 meters deep.
  • Each bench to be laterally supported using mesh reinforced shotcrete (4000m2), further supported by soil nails. A total of 27 900 linear meters will be drilled in this location.
  • The existing cut slope will be cut back, with horizontal drainage drilled into the cute face, and geopipe collectors introduced.
  • Once the slope has been stabilized by introducing the measures above, a Mechanically Stabilized Earth Wall will be constructed, to the full height of 24m to re-instate the existing road alignment with concrete barriers introduced for safety.

Site 2 – Xesi N2 Section 19 km 63.5

  • Construct a 30m long, 600mm diameter secant pile wall along the edge of the road where the failure has occurred.
  • Construct a capping beam on the secant pile wall.
  • Construct erosion protection downslope of the secant pile wall.
  • Reinstate collapsed gabion wall and construct associated drainage.

Site 3 – Isinuka R61 Section 8 km 3.5

  • Construct a temporary bypass to safeguard against risk of collapse of current road.
  • Introduce coarse rockfill to wahaway section, with a geotextile separation layer between existing fill and rockfill.
  • Dynamically compact rockfill.
  • Reinstate existing alignment.
  • Introduction of stormwater drainage upslope and downslope of washaway as a preventative measure.

Site 4 – Second Beach road in Port St Johns

  • Introduce improved drainage measures.
  • Excavate and reinstate washed section of road.