The Panama Canal famously had to deal with a lot of mud, clay, and unstable rock, causing many landslides during and after construction.
The geology of Panama is quite complex and the isthmus is only 4 million or so years old. "The geology of Panama includes the complex tectonic interplay between the Pacific, Cocos and Nazca plates, the Caribbean Plate and the Panama Microplate" - https://en.wikipedia.org/wiki/Geology_of_Panama
Looks like Panama City is working on a monorail tunnel to go under the Panama Canal for Line 3. https://www.herrenknecht.com/en/references/referencesdetail/... mentions the complex geology for the TBM has "Heterogeneous ground; La Boca Formation: Sandstone, siltstone, tuff, mudstone, pyroclastic rocks; Tucue Formation: Basalts and andesits; Panama Formation: Tuff, sandstone, agglomerate".