高速铁路40m跨箱梁预应力混凝土试验台座设计与施工技术

Design and Construction Techniques of the Pre-Stressed Concrete Test Bed for the 40 m-Spanned Box Girder of High Speed Railways

高速铁路箱梁试验台座是指用于提供箱梁加载试验反力的地下构筑物,目前,我国各铁路箱梁场采用的试验台座主要有重反力式和抗拔桩式两种。为了满足中国铁路首榀跨度40 m预制简支箱梁的研究需要,考虑到40 m箱梁的自重和跨度均大于现行的32 m箱梁,并且在研究过程中试验工况繁多,所需加载力值大,设计了一种鱼腹式预应力钢筋混凝土试验台座。在台座施工过程中,通过优化施工方案,解决了深基坑边坡防护、大体积混凝土施工、预埋吊带精确定位等技术难题。通过在40 m箱梁研究课题中的实际工程应用,该试验台座不仅满足了试验需求,而且减少了混凝土用量、节约了成本、提高了试验效率,取得了比较显著的社会和经济效益。

Test beds of box girders for high-speed railways refer to the underground structures used to provide box girders with loading test reaction.Right at present,there are chiefly two types of test beds used in various railway box girder yards in China:the heavy reaction type and the uplift pile type.In order to meet the needs of the research into the first 40 m-spanned prefabricated simply-supported box girder for Chinese railways,and also considering the facts that both the dead weight and the span of 40 m-box girder are larger than those of the existing 32 m box girder,and there are more complex test conditions and larger loading force involved in the research process,especially designed here is a fish-bellied pre-stresed reinforced concrete test bed.During the construction of the bed,the difficult technical problems such as the protection of the side slope of the deep foundation pit,the construction techniques of mass concrete,the precise positioning of pre-embedded suspension belts and the like are solved by means of optimizing the construction schemes.Through the application of the 40 m box girders to practical projects,it is found that the test bed not only meets the test requirements,but also helps reduce the consumption of concrete,save the cost,improve the test efficiency,and achieve remarkable social and economic benefits。