"建筑物沉降" can be translated into English as "building settlement" or "structure settlement".
"Building settlement" is a common and straightforward term used to describe the downward movement or sinking of a building due to various factors such as soil compression, groundwater level changes, or poor construction.
"Structure settlement" is a more general term that can refer to the settlement of any type of structure, including buildings, bridges, dams, etc. In the context of buildings specifically, both terms are often used interchangeably, but "building settlement" is more commonly associated with residential or commercial buildings.