What is Trenching?

Dan Cavallari

Trenching is a form of excavation in which a large hole is dug; the hole itself is usually quite deep but not very wide, and it is often dug to be long. Trenching is common in construction, especially when installing underground pipes, wires, or structural supports. The practice of trenching is also common in military applications to protect front line troops from gunfire or other hazards. Large trenches can be damaging to a landscape if not properly dug and re-filled after use, and digging trenches is a hazardous job, as the walls of the trench are prone to cave-ins if not properly supported on either side.

In warfare, trenching was often done to provide an obstruction between opposing forces.
In warfare, trenching was often done to provide an obstruction between opposing forces.

A trench digger can be used for trenching, or it may be done by hand with a shovel or pickaxe. Larger trenches are difficult to dig by hand, so a motorized machine has been specially designed to do the job. Trench diggers come in a wide range of sizes to accommodate the digging of many different sizes of trench. Smaller trench diggers are small enough to be operated by one person pushing the digger along the area to be trenched. Larger trench diggers, common in construction settings, are massive machines that must be driven. A large, saw-like arm is lowered to the ground to dig the trench.

Trenches are not as wide as they are deep.
Trenches are not as wide as they are deep.

A trenching differs from simple hole digging because a trench is generally not as wide as it is deep. It is also usually very long, rather than isolated in one area or built in a circular shape. A trench's shape is exactly what makes it hazardous: the walls of the trench are long and unsupported, and since the hole is deep, the lack of support runs deep as well. Trenches cave in easily, causing a hazardous work environment for anyone inside the trench. In construction sites, metal supports are usually placed inside the trench to keep it from caving in.

In warfare, trenching was often done to provide an obstruction between opposing forces. With the advent of firearms, the trenches were used as shelter from bullets and shrapnel. In many cases, elaborate mazes of trenches were built, often by hand using shovels and other hand tools, to provide more strategic positioning against the enemy. Many times throughout history, trenches were combined with underground tunnels to allow troops to move from one site to another without being detected. The practice of trenching has been around for thousands of years for military, farming, and construction purposes.

A pickaxe may be used to dig a trench by hand.
A pickaxe may be used to dig a trench by hand.

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Discussion Comments


@Izzy78 - That is quite a story. I imagine it was one of those stories that the class was stone dead silent once he talked about the seniority he had. I know people that have dug ditches and they have said that it is the worst job they have ever had doing it by hand. It hurts really badly on the back and they have told me that they have gone to the chiropractor several times for him to adjust the same vertebra. The chiropractor has also stated that this is common among those who dig quite a bit, them injuring the same vertebra.


When I was in college a professor told me a story of after he graduated high school. He worked instead of going to college and dug deep trenches to lay pipes. He talked about how scary it was climbing down to the bottom to lay the pipes down because if the pile of dirt that they had just pulled up fell on top of them they only had five or six minutes to get the workers out. He followed this point up by saying that by the end of the summer, even though he had just been hired, he had the most seniority of anyone on staff besides the foreman.

I do not know why he said it but it makes me think that either everyone quit due to the dangers or that some workers had died on the job. This is something that people have to keep in mind when they are digging trenches. Sometimes, even though it is cost effective, it is not the best idea to dig a trench on your own, especially a deep one. I can see this being a major problem in poor, under-developed countries.


When my son went on a missions trip to South America, one of their duties was to build a five foot trench.

Since they didn't have any kind of trenching machine available, this was all done by hand with shovels. There were several men who were working on this project, but it was still a pretty slow process.

He said you don't fully appreciate the machines until you have to dig something like this by hand. It can be done, it just takes a lot of muscle, time and hard work.

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