后张预应力梁封端缝渗漏治理

Repairing Leakage of Closed-End Cap Cracks in the Post-Tensioned Beam

由于后张预应力梁封端混凝土与梁体混凝土的浇注时间不同,形成封端缝,进而造成封端混凝土渗漏并引起锚具锈蚀和预应力的损失,严重影响行车安全.文中提出了一种能在12 cm(及以上)的狭窄伸缩缝环境下对封端缝渗漏进行治理的方案.首先改进了适用于该狭窄环境的基面清理工具,通过实验室模拟试验、材料性能测试和数值模拟,证实了本基面清理工具的实用性和本方案的可行性,进而将该方案成功的应用于神朔铁路大柳塔—府谷段6孔梁的现场渗漏治理.为检验治理效果,开发了一种集信号输出与数字采集于一体的渗漏检测仪样机,测试对比表明,样机具有较高的精度和较大的量程,完全可以满足工程需要.

Because of beam end cap and the beam poured at different time in the post-tensioned concrete beam, the cracks would occur in beam end cap, and then water is infiltrated into the beam, which causes the corrosion of anchor as well as the loss of post-tension, which could result in severe traffic safety problems. In this paper, we describe a program for repairing leakage on the beam end cap, which can be applied at a narrow expansion joint above 12 cm in width. Firstly, we modify the equipment to clean up the corroded concrete in the expansion joint. Based on the laboratory experiment, properties test of materials and numerical simulation, we confirm the equipment is practical and the program is feasible. Then, the program is successful in repairing 6 beams in the Shenshuo railway Daliuta-Fugu Line. In order to test the effect of repair, we design a new leakage detector for outputting data and signals concurrently. The results show that the detector is of high accuracy and large measuring range, thus engineering requirements can be met.