双层管棚处理连拱隧道下穿既有公路施工技术

Construction technique of making continuous arch tunnel to under-cross established highway by double-decked pilot piles

根据土江冲隧道的工程概况，分析了双层管棚预加固方案的可行性及管棚参数，介绍了双层管棚的施工技术，说明了其施工效果，保证了既有公路的安全和隧道的顺利施工。

According to general condition of Tujiangchong tunnel project, the author analyzes the feasibility of double-decked pilot pipes prestrengthening scheme and its pilot pipes parameter, introduces its construction technique, and illustrates its construction effect, in order to ensure the security of established highway and smooth construction of tunnel.