crumbling

if a building or piece of land is crumbling, parts of it are breaking off 坍塌；损坏；崩裂
buildings crumbling into dust
渐渐坍塌的建筑物
crumbling stonework
不断破裂的石制建筑
The cliff is gradually crumbling away.
峭壁正在逐渐崩坍。