桩间距对混凝土扩盘桩双桩抗拔承载性能试验研究

Experimental study on effect of pile spacing on pull-out bearing performance of double piles of concrete expanded disk pile

混凝土扩盘桩(以下简称CEP桩)为一种新型变截面桩基础,与传统直孔灌注桩有着截然不同的桩身构造,相较于直孔灌注桩,其抗拔承载性能更为良好,施工过程也更加经济、绿色、节能、环保,在实际工程中也被逐渐应用。CEP桩在竖向受拉作用下,桩间距是影响桩基础抗拔承载性能的重要因素。本文通过小比例半截面桩的试验方法,研究桩间距对双桩基础抗拔承载性能的影响。通过对比分析得出结论:CEP双桩的破坏过程与单桩基本相同;承力盘同位布置更为合理,且桩间距越大,承载能力越高;当需要错位布置承力盘时,应将最上盘布置在远离土体表面处。为群桩的研究奠定了基础,进一步完善了混凝土扩盘桩的理论体系,也为CEP桩在实际工程中的推广提供了理论支持。

Concrete tray pile(hereinafter referred to as CEP pile)is a new type of variable section pile foundation,which has a completely different pile structure from the traditional straight hole grouting pile.Compared with the straight hole grouting pile,its tensile bearing performance is better,and the construction process is more economic,green,energy saving and environmental protection.It is also gradually applied in practical projects.The distance between piles is an important factor affecting the tensile bearing capacity of CEP piles under vertical tension.In this paper,the influence of pile spacing on the tensile performance of double pile foundation is studied by the test method of small proportion half-section pile.Through comparative analysis,it is concluded that the failure process of CEP double pile is basically the same as that of single pile.The bearing plate is more rationally arranged in the same position,and the greater the pile spacing,the higher the bearing capacity;When load bearing plates need to be dislocated,place the top plate away from the soil surface.This paper lays a foundation for the study of pile group,further improves the theoretical system of concrete reaming pile,and also provides theoretical support for the popularization of CEP pile in practical engineering.