一种灌注桩超灌混凝土提前处理工装的应用

The Application of a Kind of Pre-Treating Tooling to the Over-Poured Concrete of Cast-in-Place Piles

在工程领域,水下钻孔灌注桩应用极为广泛,其工艺缺陷导致上部混凝土不可避免与泥浆及部分沉渣混合。因此,水下浇筑混凝土过程中采用超灌混凝土方法,一般超灌高度不小于0.5 m,后期将超灌混凝土进行破除,但随之衍生出了一系列问题。北京地铁17号线工程,采用一种水下钻孔灌注桩超灌混凝土提前处理工装替代常规超灌混凝土破除工艺,并介绍了工装的结构及应用。结果表明,相比常规破除工艺,该工装能够有效地提高钻孔灌注桩施工效率,省去破除工时和费用,避免了破除过程中对桩体主筋的损伤,保证了施工质量。

In the field of engineering, cast-in-place underwater bored piles are extremely widely used. However, due to its technical defects, the upper concrete is inevitably mixed with mud and some sediment. Therefore, the method of over-pouring concrete is often adopted in the process of pouring underwater concrete. Generally speaking, the over-poured height of concrete is no less than 0.5 m. At the later stage, the over-grouted concrete will be broken down and removed, but a series of problems may emerge. As far as the project of Line 17 of Beijing Metro is concerned, the pre-treating tooling is adopted for pouring underwater concrete for the construction of the underwater bored pile of the metro instead of the conventional technology of first over-pouring concrete and then breaking down and removing the over-poured parts. Introduced in the present paper are the structures and application of the tooling. The result shows that, compared with the conventional technology of first over-pouring concrete and then breaking down and removing the over-poured parts, the tooling introduced above may much help improve the construction efficiency of cast-in-place bored piles, save the construction time and the cost of demolition, avoid the damage to the main reinforcement in the process of the demolition, with the good construction quality ensured.