箱形地道桥作为穿越既有铁路的下跨结构在软土地基应用已十分普通。对于两孔以上的箱形桥,在施工顶进作业中设计常要求利用一孔已顶进到位的箱形桥作为施工便梁的临时支座。设计文件中,通常列出了箱内的支撑费用但并不明确施工便梁支座支承于箱形桥上的具体位置,也不对此时箱形桥的地基强度及基础的稳定性进行检算,而往往不少作业人员仅凭感性经验布置便梁,没有结合综合施工条件、仔细考虑地域地 Box-shaped tunnel as a cross-track through the existing railway structures in the soft ground application has been very common. For box-shaped bridges with more than two holes, the design of jacking operations in construction often requires the use of a box-shaped bridge that has been jacked in place as a temporary support for the construction beams. The design document usually lists the support costs in the box but does not specify the specific location where the support beam supports are supported on the box bridge and does not check the foundation strength and foundation stability of the box bridge at this time , But often a lot of homework staff only by the emotional experience of the layout of beams, not combined with the comprehensive construction conditions, carefully consider the geographical