Question: what are caissons used for?
Answer: In geotechnical engineering, a caisson (/ˈkeɪsən/ or /ˈkeɪsɒn/; borrowed from French caisson, from Italian cassone, meaning large box, an augmentative of cassa) is a watertight retaining structure used, for example, to work on the foundations of a bridge pier, for the construction of a concrete dam, or for the repair ...