- underground road
- underground service drilling hole
- underground sewage treatment facility
- Underground Space Design
- underground space environment
- underground space management
- underground space master plan
- underground space property right
- underground space resource
- underground space survey
- Underground Spring Trilogy
- underground station
- underground station drainage
- underground stope arrangement optimization
- underground storage and facility
- underground storage of lined
- underground stormwater storage tank
- underground structure of oil and gas field
- underground substation
- underground survey
- underground tank
- underground thermal energy storage
- underground thermal pollution
- underground town of Japan
- underground trackless auxiliary vehicle