pilot hole

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。