真空压浆技术在跨渠桥梁施工中的应用

摘要

In construction of the cross-canal bridges in South to North Water Diversion project, the common grouting was used for post-tensioned prestressed concrete beam. After the grouting, the safety of the bridge was influenced by the problems such as void and insufficient density. So, the vacuum grouting technology was adopted to ensure grouting quality. The principle, construction technology, steps and points for attention in vacuum grouting were introduced. The practice showed that the vacuum grouting could reduce bleeding, maintain the pressure of the slurry and ensure slurry fullness in the pipeline, avoid the cracks and shorten the grouting time and the reliability and durability of post-tensioned prestressed concrete beam could be improved.%南水北调中线工程跨渠桥梁建设中，后张预应力混凝土梁使用普通压浆方法，管道压浆后出现空隙、不密实的问题，直接影响到桥梁运行安全，因此需要采用真空压浆技术以保证压浆质量。介绍了真空压浆技术的原理、施工工艺、压浆施工步骤和施工注意事项。工程实际表明，采用真空压浆技术可以减少浆体孔隙泌水现象、保持浆体稳压并充满整条管道、消除裂缝并保证浆体充盈度、缩短压浆时间，能够提高跨渠桥梁后张预应力混凝土梁的可靠性和耐久性。