JOHANNESBURG - More than a month later, investigations are still underway into the subsidence affecting the N12/N3 northbound slow lane in Bedfordview.
The lane, just before the Van Buuren off-ramp, was cordoned off in late March after the South African National Roads Agency Limited (SANRAL) identified possible sinkhole activity in the area.
SANRAL said instability along the stretch is causing the road surface to gradually sink.
Spokesperson Lwando Mahlasela says the affected lane remains closed, although traffic disruptions have been limited.
He adds that before repairs can begin, the full extent of the damage must be assessed. This will include a geophysical survey to detect any underground voids.
READ: SANRAL closes N3/N12 slow lanes over ground instability
Depending on the findings, repairs could take anywhere from eight months to up to 18 months, depending on the intervention required.
A similar sinkhole at the Flying Saucer Interchange in Centurion, which affected the southbound slow lane, took approximately 15 months to repair.
How are sinkholes fixed?
One common method is the filter method, which involves plugging the sinkhole’s opening with large rocks or boulders.
The cavity is then filled with suitable material, followed by the placement of geotextiles and the reconstruction of the road layers.
Alternatively, a grout mixture can be injected underground through drilled boreholes arranged in a grid pattern.
This process fills any voids beneath the surface, stabilising the ground and preventing further collapse.