大跨度连续梁上跨铁路营业线施工安全防护技术

摘要

T he part of the approach over pier No .78~pier No .81 of New Baishatuo Changjiang River Bridge on Chongqing‐Guiyang Railway in Chongqing is continuous beam structure with a continuous unit of (68+128+68) m ,crossing the electrified railway specially‐used by Luohuang Power Plant .To ensure the construction safety of the part of bridge crossing operational railways under complex conditions ,two schemes were proposed ,including the construction of the beams u‐sing form travelers after the erection of protection roofs and frames and the fully‐closed construc‐tion by form travelers .By scheme comparison and selection ,the latter was finally chosen and im‐plemented .The structure of the fully‐closed form traveler was designed and calculated .The clo‐sure protection system of the form traveler itself incorporates the protection platform under the form travelers ,the surrounding protection mesh ,protection mesh for the top cross beam of the form travelers and the protection facilities on the surface of the beam .The protections for the op‐erational railways include the site‐based construction protection ,mechanical protection and signal protection .The safety engineering practice proves that the structure of the form travelers used to the construction is safe and reliable ,and the protection techniques adopted ensured the safety of the operation of the railways under the beams .%重庆渝黔铁路新白沙沱长江特大桥引桥78号～81号墩为一联（68＋128＋68） m连续梁，上跨珞璜电厂专用线电气化铁路。为保证复杂条件下上跨铁路营业线的施工安全，对先搭设防护棚架防护后进行挂篮施工和全封闭挂篮施工2种方案进行了比选，最终选用全封闭挂篮工艺施工。对全封闭挂篮结构进行设计计算，挂篮自身封闭系统防护包括挂篮下方防护平台、周边防护网、挂篮上顶横梁防护网、梁面防护等；营业线防护包括施工驻站防护、机械防护和信号防护等安全防护。工程实践表明，该挂篮施工结构安全可靠，所采取的防护技术保证了梁体下方铁路营业线运行安全通畅。