It almost looks like some big earthmoving equipment came through here and dug up the bottom of the cave.
ELAM:看起来好像有一些大型土方设备从这里经过,挖出了洞穴的底部。
英语百科
Earthworks (engineering)
(重定向自Earthmoving)
Earthworks are engineering works created through the moving or processing of parts of the earth's surface involving quantities of soil or unformed rock. The earth may be moved to another location and formed into a desired shape for a purpose. Much of earthworks involves machine excavation and fill or backfill.