异型同步灌注桩工程试验研究

Engineering Experiments of Synchronously Cast-in-Situ Pile with Special Cross Section

本文论述一种新的灌注桩成桩方法及设备。其桩管比预制桩尖小许多，管身有进料孔，管底有出料孔，在打入桩尖的同时混凝土就自动灌入桩尖挤出来的空隙中。即成孔与灌注是同步进行的。由于是有压灌注，从而避免了断桩，成桩的大小和形状完全取决于桩尖，所以可做成不同形状的桩。本文推荐三角星形截面的灌注桩。通过工程试验，证明异型同步灌注桩不但节省材料，还能提高承载力。

A new type of forming method for cast-in-situ pile and its equipment are elabora-ted in this paper, in which the processes of hole forming and concrete pouring are carried out syn-chronously,and the cross section of pile can be made into any shape。The size of the tubular pileshaft is much smaller than that of the precast pile tip.The tubular pile shaft has feeder openingsand the pile tip has concrete outlets ,so that in the process of hole forming the concrete will auto-matically pour into the void formed by pile tip pressing. As the concrete is pressure─grouted,thephenomenon of pile breaking will thus be avoided. The size and shape of the cross section of pileare entirely dependent on those of the pile tip,so the pile can be cast into any shape. Engineeringexperiments show that the triangular star section cast- in- situ pile,recommended in this paper, byusing the forming method presented can not only save materials,but also increase the bearing ca-pacity of the pile.