pile up

transitive idiomatic intransitive

(transitive) To form a pile, stack, or heap. / (idiomatic, intransitive) To collect or accumulate, as a backlog.

Japanese Meaning

（他動詞）山積にする、積み上げる、積み重ねる / （自動詞・慣用表現）積もる、たまる、蓄積する

They asked the volunteers to pile up the sandbags along the levee before the storm.

彼らは嵐の前に堤防沿いに土嚢を積み上げるようボランティアに頼んだ。

Sense（1）

(transitive) To form a pile, stack, or heap.

The kids piled up their boots and coats by the back door.

Sense（2）

(idiomatic, intransitive) To collect or accumulate, as a backlog.

The requests piled up while she was away.

piles up

（ present singular third-person ）

piling up

（ participle present ）

piled up

（ participle past ）

piled up

（ past ）