"建筑物沉降" can be translated into English as "building settlement" or "structure settlement".
"Building settlement" is more commonly used when referring to the sinking or subsidence of a specific building.
"Structure settlement" is a broader term that can encompass various types of structures, including buildings, bridges, dams, etc., but it can also be used specifically for buildings.
In most contexts, especially when discussing civil engineering or construction, "building settlement" would be a suitable and accurate translation.