管棚-大断面箱涵暗顶技术在下穿公路工程中的应用及分析

Application and analysis of forepoling and large-section box culvert jacking for underpass highway construction

某宽断面公路与公路交叉工程,为在施工期间不中断既有干线公路的正常通行,采用管棚支护下的大断面箱涵暗顶法进行无损下穿,规模大、技术难度高。介绍了管棚、箱涵及其配套设施的设计与制作情况;重点分析说明了"吃土顶进、泥浆润滑"的暗顶施工工艺;论述了对箱涵姿态等进行全过程独立监测的必要性及监测内容;实时指出了该工程在具体操作过程中存在的不足之处。在此基础上再考察比较其他类似工程,着重在公路下穿工程建设的宏观管理方面,特别是方案的制定、技术经济比较、决策选择等方面,总结了经验教训,认为总体上采用下穿方案是适宜的,但更应该因地制宜采取合适的下穿方式,并要未雨绸缪制定周密的施工工艺,才能又好又快地实现建设意图。对于最复杂的暗顶下穿方式,得力的参建队伍、可靠的支护、有效的润滑这三个最基本的要素缺一不可,否则只能事与愿违。这些有益的结论和体会,可为其他类似工程提供借鉴。

For the construction of a underpass large-section highway, in order to reduce disturbance to normal traffic of the existing highway, large-section box culvert jacking and forepoling have been employed. The design and manufacture of the forepoling and the box culvert and their supporting facilities are introduced. The jacking technique of＇pushing through excavating soil and slurry lubrication＇ is analyzed emphatically, and the necessity and content of independent attitude monitoring of the box culvert are also discussed. Using this project and other similar projects, the experiences and lessons learned in macro-management of project construction, especially in the aspects of scheme selection, technical-economical comparison and decision making, are summarized.