超大直径隧道衬砌
super-large diameter tunnel lining
大直径径向渗透率仪
full diameter radial permeameter
大直径直缝焊管
Large- sized straight weld pips
large-diameter butt welded pipe
large diameter longitudinal welded pipe
Large-sized straight welded tube
U形衬砌渠道
the lining of U Canal
U-shape canal with concrete lining
半封闭圆形衬砌
partially sealed circular lining
变截面液压台车衬砌
hydraulic truck lining with variable sections
不衬砌地下洞室
unlined underground cavern