塑料套管混凝土桩拓展工艺试验

Experiment on Developing Technology with Plastic Tube Cast-in-place Concrete Pile in Construction

针对塑料套管混凝土桩(TC桩)在现场施工中明显的扩孔效应和前期承载力发挥不足等问题,开展了TC桩拓展新工艺试验研究。介绍了TC桩管外注浆、塑料套管粒料注浆和塑料套管壁外管内注浆施工工艺,针对各类桩型开展了28 d单桩承载力静载荷试验,并通过埋设钢筋应力计的形式研究了管外注浆TC桩与普通TC桩在荷载传递机制上的异同。研究结果表明:管外注浆新型工艺能有效地增加TC桩的前期承载能力,相对于普通TC桩,28 d单桩承载力提高了117%。塑料套管壁外管内注浆TC桩相对于普通TC桩,28 d单桩承载力提高了50%。粒料注浆能够有效避免TC桩在挤土压力作用下出现爆管的情况。

Plastic tube cast-in-place concrete pile( TC pile) had obvious reaming effect and pre-bearing capacity shortage in the construction. In view of this issue,developing new technology test for TC pile was carried out. This paper introduced the TC pile tube grouting,plastic tube pellets grouting and plastic outer tube wall grouting. For all types of piles,a 28 d pile capacity static load test was performed. The similarities and differences between common TC pile grouting and tube grouting TC pile on load transfer mechanism by embeding steel-strain gauges were studied. The results show that the new tube grouting technology can effectively increase the pre-carrying capacity of the TC pile. Compared with the normal TC pile,the 28 d pile capacity increases by 117%. The 28 d capacity of plastic outer tube wall grouting TC pile increases by 50%relative to the normal TC pile grouting. Gravel grouting can effectively avoid TC pile bursting pipes under soil compaction pressure.