The story is relatively recent, I think.
It's about a ... primitive? caveman? warrior type person who following an earthquake, IIRC, falls into a sealed chamber which turns out to be part of an underground knowledge repository/library.
The local friendly AI wakes up when he does his best Jules Verne and Stuff Happens.
Can anyone remember what story this is?
here's the link. you missed the "a" in Dai Stiho :)
https://storiesonline.net/s/23172/the-last-library
I can't remember an earthquake in this one, but https://storiesonline.net/s/56778/heirs-to-the-ancients by Fick Suck matches everything else.
A couple of other stories by the same author have a similar plot but this one comes closest.
Thank you @patorojo and @sunseeker, that's exactly the story I was looking for.
@Dinsdale, thank you, I will look into that as well!
If you like Heirs to the Ancients, take a look at https://storiesonline.net/s/48527/grains-of-sand by the same author.
A more recent story of his is https://storiesonline.net/s/21793/blue-hand and it is in a somewhat similar vein even if it takes a very long time to get there.
His most ambitious - read "long" - work is https://storiesonline.net/universe/362/family-volentin and a "civilisation lost" theme is one of the underlying themes there as well.