chóng​chóngzhòng​zhòng

one after another

重重 chóng​chóng frequency
one after another descriptive
appearing or occurring in a continuous sequence or in great numbers, typically referring to abstract obstacles

Despite facing many difficulties, he still didn't give up.

layer upon layer descriptive
consisting of many layers or overlapping tiers, often used for physical scenery or dense barriers

Mountains rise one after another ahead, shrouded in mist.

重重 zhòng​zhòng
heavily descriptive
with great force, weight, or intensity; in a severe or serious manner

He slammed the book down on the table.

Frequency

Movie subtitles
5.31 per million appears in 3% of films
Written text
12.1 per million

Sources

Definitions
CC-CEDICT