underground air矿内空气
undergroundadj.地下的;秘密的adv.在地下;秘密地n.地下;地铁;地道;秘密活动
underground openings and tunnels地下洞室群
underground pressure observation矿压观测
Underground pipelines and cables地下管线
underground big-space building地下大型建筑
underground artificial structure地下人工结构
underground engineering envelope地下工程围护结构
underground hot-water features地下热水特征
underground mining from open pit露天转地下开采