Those had better be (for the Nork soldiers’ sake) pretty thick walls. We now have a variety of weapons, including specialized cruise missiles, that can penetrate a long way into soil or sand.
There is also the old (WW2) British concept of, instead of penetrating the target, penetrate deeply just to the side of it, blasting a void into which the target collapses.
Web searches will turn up plenty of reading material. :-)
Barnes Wallis was a genius.