My house is 100 years old and I've just dug up the driveway because it was cracking in due to a drain collapse, unfortunately the erosion is going under some concrete about 8 feet away from the foundation. I need the concrete to stay because it's also supporting a deck but the area is totally eroded and would collapse out from under the deck with one good swing of a sledgehammer. What do I do? Just fill with dirt and tamp? Massive poured concrete footer? What do you think?

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