掌子面 meaning in Chinese

drift face
heading face

Geological information research at tunnel excavating face by image compiling and identify technology
隧道掌子面地质信息数字编录识别技术研究
The practice proves that this method would consolidate the ground and stabilize the working level
通过实践，这种施工方法对于加固地层，保证掌子面的稳定起到了很好的效果。
The influence radius of tunnel excavation on crown vertical displacement is equal to tunnel radius and the influence radius on horizontal convergence displacement is 1 . 5 times of tunnel radius
同时，测点距掌子面1倍洞径和1 . 5倍洞径时，拱顶下沉位移及水平收敛位移分别趋于稳定。