cave-in 
noun
1A collapse of a roof or underground structure: a mine cave-in...
- Newspaper reports talk of mine cave-ins and shaft collapses.
- They go deeper and deeper underground, with cave-ins making rescue impossible, completing the classical haunted house structure.
- Surface subsidence also causes safety concerns for the public because of roadway cave-ins or structures and buildings tilting or even collapsing.
1.1An instance of yielding or submitting under pressure: the government’s cave-in to industry pressure...
- Labor accuses him of one of the quickest cave-ins in political history but Queensland Opposition leader Lawrence Springborg has sprung to the new senator's defence.
- The cave-in started in the first over with Scott Richardson's slash at Graeme Welch ending up in Christopher Bassano's hands at gully.
- This kind of presentation is just a cave-in to the politically correct crowd.