高速铁路900t预制箱梁支座板混凝土空洞防治技术

Preventive and Repairing Techniques Against Cavities in Concrete of the Supporting Seat Slabs for the 900 t Pre-Cast Box Girders of the High-Speed Railways

在我国高速铁路实际工程中大量采用了900 t预制箱梁,为保证行车安全及结构耐久性,对高速铁路预制箱梁工程质量要求很高。结合预制过程中支座处混凝土易出现空洞的实际情况,分析了支座处出现空洞的原因主要与构造及施工工艺有关,对此采用改性环氧树脂灌缝胶作为填充材料压浆处理,并提出了预防支座处混凝土空洞的具体措施。实践表明只要加强过程控制,改进施工工艺,可避免预制箱梁支座混凝土空洞的产生。

Owing to the fact that a large number of 900 t pre-cast girders are used for projects of the high-speed railways in our country,we are very strict with the quality requirements of the box-girder-pre-casting projects of the high-speed railways to ensure the safety of the railways and the duration of the structure.With the liability of cavities in concrete near the seats in the course of pouring concrete taken into account,the causes for the appearance of cavities in concrete near the seats are analyzed in the paper and it is found that the appearance of cavities in concrete is chiefly relevant to the structural forms and the construction processes.To solve the problem of cavities in concrete,the property-changed seam-sealing epoxy glue is used as filling material when the slip-casting is performed,with other specific cavity-preventing measures put forward.Practice shows that cavities in concrete near the supporting seats of the pre-cast box girder can be avoided as long as the process control is strengthened and the construction processes are improved.