Sinkhole resists all repair efforts

The Sheffield Drive sinkhole that occurred on April 5 keeps on biting back at all efforts to get it repaired.

Since its initial collapse, a lot of work has gone into it to get it fixed up. Heavy machinery was brought in to open up the whole channel down to the level of the stream. Concrete works were introduced to build a funnel with U-shaped concrete structures right through. Brickwork on both sides took place to act as protection to the material above and to guide the expected water to the funnel.

On the one side of the channel we have quite a few conduits of infrastructure that crosses it. This includes telecommunications infrastructure and possible electricity cable, as well as the main water supply line to the Sheffield Beach area. Some gum poles were put across the channel to provide some kind of support but during the works these were all suspended in the air. After all these initial preparations took place, the soil was re-introduced and the channel was filled up and compacted. On top, gravel and tar mix was used to build a resilient foundation to the final tar layer. Last weekend, most of this was done and all that was outstanding were the kerb stones and the final tar layer.

It seems that in the process of the compacting of the soil, the infrastructure was not properly supported and the process brought pressure onto it. The water pipe, specifically, was of a hard clay-based material and obviously did not have enough flexibility to deal with this downwards force. On Tuesday morning July 7, the water pipe ruptured and the high pressure water then effectively destroyed most of the works above and around it. The damaged part was cut out and a PVC piece was fitted in its space and connected and secured with high pressure clamps. It left Sheffield Beach without water for the whole day and without electricity for most of the morning.

This morning of the 10th, the pressure got to the pipe again and the same thing happened. Sheffield Beach is without water once again. Lots of water have been wasted in this process. It has caused a lot of inconvenience to residents who are already heavily burdened with the water shedding issue.

CHRIS KLEYNHANS

Sheffield Beach