The South African National Road Agency (Sanral) has sent out a warning to notify road users of possible road closures due to “a new sinkhole that formed along the R21 near Olifantsfontein” near Midrand.
“Two sinkholes formed on Monday afternoon just before 16h00 along the R21 northbound carriageway towards Pretoria, just after the Olifantsfontein interchange,” said Louw Kannemeyer, Sanral’s engineering executive.
“One sinkhole developed just outside our road reserve fence boundary, and the second one immediately adjacent to the edge of the R21, penetrating about two meters underneath the road up to the slow lane and five to six meters deep currently,” said Kannemeyer.
He further said that cracks formed in the road surface in the outer two slow lanes of the R21, resulting in the immediate closure of these lanes.
Kannemeyer said that Sanral engineers have already performed preliminary assessments of the new sinkhole and the agency is in the process of appointing geotechnical engineering specialists who are able to assist with the required investigations.
While the investigations are carried out, Sanral will install “New Jersey concrete barriers” in the road in a similar fashion to the recent N1 sinkhole to control traffic flow.
The barriers will remain in place until the assessments are completed and “remedial measures” implemented.
“How long that will take is dependent on [the] extent of the sinkhole, which at this stage remains to be quantified,” said Kannemeyer.
“The R21 northbound will be reduced to two lanes in the direction of Pretoria just after the Olifantsfontein interchange for the foreseeable future, resulting in associated congestion during peak hour periods.”
“Road users are advised to take this into account in their daily planning and consider alternative routes such as M18 and M57 which run parallel to the west of the R21 in the vicinity of the affected area,” said Kannemeyer.