The Chinese word for tunnel is
隧道

suì dào

Chinese Definition

Components
隧
1. tunnel; underground passage
道
1. way; path; road
道路 - road
2. (historical) circuit: an administrative division of late imperial China comprising 2 or more commanderies
3. (rail) track
上道作業 - maintenance on rail tracks
1 道通過 - passing on track 1
4. method; principle
5. (Buddhism) the Marga; the Way of bodhi or enlightenment leading to nirvana through spiritual stages
6. (philosophy, Taoism) the Way; the Tao; the Dao: the way of nature and/or the ideal way to live one's life
7. (Christianity) Logos; the Word
8. Short for 道教 (Taoism)
9. Short for 道士 (Taoist priest)
10. (religion) doctrine; teachings
傳道 - to preach
11. (literary) to say; to utter
能說會道 - can talk really well (idiom)
一道閃電 - a bolt of lightning
一道河 - a river
一道縫 - a crack
一道彩虹 - a rainbow
一道籬笆 - a fence
一道菜 - a dish of food
一道公文 - a proclamation
一道命令 - an order
12. (obsolete) Alternative form of 導 (to direct; to guide; to lead; to conduct)