Cut and Cover Technique
Cut and cover is one of the fastest and easiest ways to construct a tunnel in soft, shallow ground.

Here's how the cut and cover method works:
Tunnel diggers cut an open trench in the earth and drop a pre-made tunnel into it. Once the tunnel is in place, the workers cover it back up with soil. Simple, right? Not quite. Unfortunately, life is never this easy for engineers ...

Cut and cover is a fast, cheap, and easy way to build a shallow tunnel in soft soil, but it's not always practical. Tunnel diggers must gouge a massive hole in the earth to make room for the tunnel. This is a real problem in cities, where skyscrapers, roads, and railroad tracks crisscross the surface of the ground. Since you can't easily move buildings and roads out of the way, cut and cover isn't always the best solution.

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