堆 vs 堆积（近义词）

1)As a noun,堆 means"an irregular pile of sth.",e.g.土堆 (a soil pile), 砖堆 (a brick pile),垃圾堆 (a rubbish pile),瓦砾堆 (a rubbles pile )etc.

1)堆，as a measure word,means"a pile of sth.or a group of people' and it can take 儿 after it.When applied to people,it often has a derogatory sense(The numeral is limited to一or几).e.g.一堆垃圾 (a pile of rubbish),两堆砖头 (two piles of bricks),成堆的问题 (piles of problems),一堆人 (crowds of people),etc

1)As a verb,堆 means"to pile up scattered things into an irregular heap".and it can take a com. plement like 成，到，满，在，etc.after it.e.g.
2)It can also be used in an abstract sense:

1)堆积，as a verb,means "to pile up",and mostly used in an abstract sense,but it can also be applied to concrete things.The words used after it are usually disyllabic so as to make up a four-character phrase. e.g.堆积而成 (pile up),堆积如山 (heap up into a mound),etc. Since 积 has a sense of accumulating,it need not take the complement满.e.g.:
2)堆 and 堆积 sometimes are interchangeable:
3)This is be cause in such a situation,the words used after are disyllabic,which suits both verbs.It is also applicable to both verbs to use"hill"to describe the pile of straws.However, in examples①②，堆 cannot be used owing to syllabic collocation. In example①of 3,堆雪人is an idiomatic phrase,and 堆积 cannot be used instead.In example③of 3 堆 can be used only because the only sentence does not have the meaning of accumulation