堆积 + 起来
The word 堆积 (duījī) means "to pile up," "to accumulate," or "to stack." It describes things gathering or building up over time or in a physical space. It can be used both literally, for physical objects, and figuratively, for abstract things like problems or emotions.
桌上的文件已经堆积如山了。
zhuō shàng de wénjiàn yǐjīng duījī rú shān le.
The documents on the desk have piled up like a mountain.
工作太多,问题不断堆积。
gōngzuò tài duō, wèntí búduàn duījī.
There's too much work, and problems keep piling up.
雪在路边慢慢堆积起来。
xuě zài lù biān mànmàn duījī qǐlái.
Snow slowly piled up on the roadside.