Longman Dictionary of Contemporary English
Wiktionary
n. (alternative spelling of cave in English) vb. (alternative spelling of cave in English)
Wikipedia
A cave-in is a collapse of a geologic formation, mine or structure which may occur during mining or tunneling. Geologic structures prone to spontaneous cave-ins include alvar, tsingy and other limestone formations, but can also include lava tubes and a variety of other subsurface rock formations. Glacier caves and other ice formations are very prone to collapse from exposure to warm temperatures or running water.
In mining, the term roof fall is used to refer to a many types of collapses, ranging from the fall of a single flake of shale to collapses that form sink holes that reach to the surface. However, roof falls in mining are not all accidental. In longwall mining and retreat mining, miners systematically remove all support from under large areas of the mine roof, allowing it to settle just beyond the work area. The goal in such mining methods is not to prevent roof fall and the ensuing surface subsidence, but rather to control it.
Usage examples of "cave-in".
Clan Gatherings were held once every seven years, and the last one was the summer before the cave-in.
They have also developed the ability to drink through their pores, an attribute that can be very handy during cave-ins.
Seismographic sensors registered some small cave-ins, but they were in adjoining side tunnels and pits, not the main shaft.
Apol, Lia, Cloe, and their band of poseurs had convinced them all that I had come to an untimely end in a mine cave-in.
Since the cave-in, they had not been able to get back into the diggings to work their claims and they had just come from the mass funeral of the six men that had been crushed to death by the treacherous yellow gravel.
Now he was flying down Main Street Hill and he could see the white-and-orange crash barriers, the smudgepots with their smoky Halloween flames marking the edge of the cave-in, he could see the tops of buildings which jutted out of the streets like the figments of a madman's imagination.
Dunneldeen, recovered from the cave-in, was operating a chattering spade bit, sweat streaming off him in the closed, hot confines of the drift.
The first vertical fault they had encountered, a seep in soft, porous stone, had cost them a dozen lives and three days' delay because of a cave-in.
A tunnel -- the second one since Wytheville -- opened up before them at the last moment, and Melissa clenched her fists, fearing washouts, fearing cave-ins.