Deformation and control of surrounding rock in 8 inclined shaft area of wushaoling tunnel 乌鞘岭隧道8号斜井区域围岩变形与控制
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Smooth finished disc flats : these “ mate ” with seat flats to give a highly efficient seal ; prevents leakage into shaft areas 光滑表面的阀板:这些阀板上的“配套”使得密封非常有效,防止泄漏到轴区域内。