What Is a Rock Fall Fence, and How Do They Work?
When most of us think of fences, we think of structures that are designed to keep people or animals in or out of an area, and that’s exactly what most fences do.
However, there are some types of fences that have a much more important function, and rock fall fences are one of those. So, let’s take a closer look at what a rock fall fence is, how they work, and where you might see them in action.
What Is a Rock Fall Fence?
The name kind of gives it away, but a rock fall fence is a type of fence that’s designed to catch, deflect and slow down rocks that might fall or roll down mountains or cliffs.
They’re usually installed in some of the most difficult conditions you can imagine for a fence, and they’re usually some of the most highly engineered fence systems you’ll find.
How Do Rock Fall Fences Work?
One of the problems with stopping rocks that are rolling or sliding down a mountain is that when they hit another hard, rigid item (like other rocks), if they have enough speed and momentum, they can kind of bounce.
The only thing scarier than a multi-ton boulder rolling down a mountain is the same boulder when it catches air!
That’s why most of the rock fall fences you’ll see around the world aren’t rigid at all. Instead, they’re made of heavy-duty mesh, high tensile cables and usually, metal rings woven together to form a kind of enormous chain mail armor.
This makes them strong enough to stop boulders but also flexible enough not to cause them to ricochet or bounce. This flexibility also means that they’re better equipped to absorb the enormous forces that are generated when a boulder does hit them.
Why Do We Need Rock Fall Fences?
In most places around the world, rock falls aren’t a problem. Deep in the mountains, where the only traffic is passing wildlife, it doesn’t matter if a rock falls down a mountain. It doesn’t even matter if a dozen rocks follow. They’ll simply land at the bottom and become part of the landscape.
However, humans love great views and scenic drives, so we’ve carved roads, tracks, and railway lines out of the side of mountains around the world. Some have steep cliffs leading to the ocean below, while others go through mountain valleys. Wherever they are, though, when there are cars on them, rock falls are very dangerous to the people using them.
In some parts of the world, people have even built homes, hotels and other structures near roads and cliffs that are prone to rock falls.
Thankfully, it doesn’t happen often that a rock fall does injure people or damage property, but when it does, it’s a big problem.
How Are Rock Fall Fences Built?
As you can imagine, from something that is designed to catch something that probably weighs more than your truck, rock fall fence construction starts with a lot of careful study and engineering. Whole teams of experts can work for years to develop the best rock fall fence strategy for a particular place.
Once that’s done, the fence materials are procured from specialist suppliers, and the whole system is installed by expert fence installers who know how to build fences that can stand up to almost anything nature can throw at them.
It doesn’t stop with building them though. To keep these fences working the way they should, they have to be carefully maintained and repaired when necessary. So it’s really a full-time job to keep a fence like this in good condition.
Where Can You Find Rock Fall Fences?
There are many places around the world using innovative fencing systems for rock falls, but one of the best-known is along Chapman’s Peak in Cape Town. This road was once closed for years after a truck-sized boulder destroyed a vehicle, but today it’s usable again, all thanks to rock fall fencing.
