It’s likely more dangerous thank bedrock tunneling frankly. Loosely consolidated sedimentary soil can easily shift and slide with relatively little outside input. A truck driving by, a rain, sprinklers, even someone walking over it.
And it only takes a small amount of dirt covering someone to crush them or suffocate them to death. Literally less than a foot depending on distribution.
Construction crews have to shore up anything higher than waist high for this reason.
A guy on our street died digging out for sewer, only ~2m deep - a side he had stacked dirt on caved in/slided and covered him. He left a wife and 2 kids. No tunnel, just unsafely stacked dirt mound.
Thank you. My partner is an architect, and while they aren’t a structural engineer, they had enough structures training in grad school to know that hobby tunnel digging is extremely dangerous. There are clearly alternative physical activities that would have all the same benefits with none of the downsides.
And it only takes a small amount of dirt covering someone to crush them or suffocate them to death. Literally less than a foot depending on distribution.
Construction crews have to shore up anything higher than waist high for this reason.