1) pilot hole drilling tool
导向孔钻具
3) pilot hole
导向钻孔
4) Drilling director
钻孔导向器
5) directional hole drilling
导向钻成孔
1.
Based on retrospection and analysis of the existing pipe roof techniques at home and abroad,according to the restrictive conditions of pile roofs in Xidan Station hidden digging section of Beijing Subway Line 4,a comprehensive construction method is chosen and successfully executed,including directional hole drilling,multiple back-reaming,combination of pull and punning.
在对国内外已有管棚施工技术的回顾与分析基础上,根据北京地铁4号线西单站暗挖段管棚设置的限制条件,充分考虑各种因素的影响,选择并成功实施了导向钻成孔、多次扩孔、前拉后夯的综合施工方法。
6) pilot drill
导向孔钻机
补充资料：第二孔(继发孔)型缺损
第二孔(继发孔)型缺损
ostium secondary defect
是心房间隔在形成上发生障碍，一般缺损较大，多在卵圆孔附近称第二孔(继发孔)型缺损。
说明：补充资料仅用于学习参考，请勿用于其它任何用途。
参考词条