客运专线桩基混凝土施工常见问题及解决方法

Problems and Countermeasures for Concrete Construction of Pile Foundations of Passenger-dedicated Railway Works

针对客运专线桩基混凝土施工中要求流动性大、保水性好及设计使用年限长等特殊要求,模拟施工实际情况,通过实验分析比较了浆体体积、聚羧酸盐高效外加剂和粉煤灰等活性矿物掺合料对混凝土工作性能的影响,结合高性能混凝土配合比设计及过程控制的实践经验,提出通过动态控制原材料品质、合理确定浆体体积和控制灌注过程埋管深度,解决客运专线桩基混凝土施工中存在的浮浆厚度过大等常见质量问题。

The concrete for the pile foundations of passenger-dedicated railway works has such special requirements as high flowability, high water retentivity and long designed service life. In the paper, the author analyses the influence on the performance of the concrete imposed by the concrete mixture volumes, the high-efficiency polycarboxylate additives and the active mineral admixtures （ such as fly ash ） respectively by means of simulating the actual construction conditions and experiments. On basis of the practical experience in the mixing ratio design and process control of high performance concrete, the author proposes some countermeasures （ including dynamic control of the quality of the raw materials, selecting proper concrete mixture volumes and controlling the buried depth of the tremie during concrete casting） for the common problems （ such as over-thick laitanee ） occurring during the concrete construction of pile foundations of passenger-dedicated railway works.