R5-m Bluff landslide repairs to see road re-open next week
Environmentally-friendly structures were put in place to restore the embankment following the landslide in February.
AT a cost of about R5-million, the repairs to the Chipstead Avenue have been completed, following the landslide earlier this year.
As a result, the the road should be open for public use within the next week.
The landslide was the result of a burst water main on Monday, 3 February, which caused the road to collapse and the embankment, which is over 100 metres high to fall to the train tracks below. This resulted in the railway line being closed for over a month following the collapse.
In order to ensure this does not recur, engineers used materials which would be able to adapt to the shifting of sand that takes place at the site. “The design entailed earth reinforced principles to stabilise the slope and the choice of materials was very important, as a rigid material structure was not viable due to potential dune sand movement.
A flexible structure with high strength was chosen. Green terramesh was used, with protruding three metre tails for structural stability filled with gabion stone. The fill material was compacted in 300mm layers to a design height of about nine metres. The front face of the green terramesh was filled with special topsoil and compost to instil fast growth of ground cover over the terramesh and in due course it will be greened over and we have a fully environmentally-acceptable solution,” said Randeer Kasserchun, deputy head of the municipality’s Coastal, Stormwater and Catchment Management department.
Residents were irate that repairs only commenced in mid-May – more than three months after the landslide. “The contract was a done on an emergency basis and authority to commence with the rehabilitation work had to be sought from the city manager prior to going out to tender,” said Kasserchun.
Not only was the embankment repaired, but the road was rebuilt and the damaged stormwater pipeline replaced. An environmentalist was then brought in to rehabilitate the land. All that remains before the road is re-opened is the replacement of the water main pipe and the addition of fencing to prevent dumping.
“My initial impressions were such that I did not think the massive hole could be filled – at least the challenge seemed financially too costly. But I have to admit I am gobsmacked at the way it has been restored and the innovative terracing of the slope. It really is an epic feat of engineering, for which those responsible merit high praise,” said ward 66 councillor, Duncan Du Bois.
