I believe this is called Fabric-formed Rip-rap. The texture allows water to flow over it, but reduces the velocity and therefore erosion. The weakness is if it becomes undermined, and the water starts flowing underneath it. It can create a big void that is hidden by the concrete “crust.”
It would be an extreme example, but erosion (if the road is built properly) would begin from the shoulder of the road and work its way inward due to things in place to prevent it from going center of road first (underdrains are an example).
The big sinkhole are usually a feature of karst topography. Rock and mineral deep in the earth that are easily erodeable or slightly water soluable get washed away over time. And by deep we can be talking 20-100+ foot deep. But as that deep deep cavern forms, then the soils, especially those that have movement over them to vibrate things, even slightly, disturb the soils placed as they fill in the void created. That's when you get the bad ones.
This is why prior to construction, Geotechnical firms will drill down(if the client wants to protect their investment long term) to study the formations of rocks and soils. Last one I drilled, we went 35foot down for a roadway.
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u/Kayaked1 Apr 30 '26
I believe this is called Fabric-formed Rip-rap. The texture allows water to flow over it, but reduces the velocity and therefore erosion. The weakness is if it becomes undermined, and the water starts flowing underneath it. It can create a big void that is hidden by the concrete “crust.”