注浆桩土接触面试验研究及后注浆抗拔桩承载特性数值分析

桩侧后注浆抗拔桩是一种新型的抗拔桩基础。借助于试验和数值手段对这种抗拔桩的承载变形特性开展了深入研究。首先进行了接触面的大型剪切试验,以揭示桩土接触面在注浆与未注浆前后其力学特性的差异性,并基于大型接触面剪切试验成果,建立了桩土接触面的修正库仑摩擦模型。将接触面模型应用到有限元数值分析,分别模拟了传统等截面抗拔桩与后注浆抗拔桩的承载变形特性。研究表明,相比传统的抗拔桩,桩侧后注浆抗拔桩的侧摩阻力得到了显著的改善,特别是深处的桩侧极限摩阻力得到了更充分的发挥,从而桩侧注浆抗拔桩的承载能力有了较大程度的提高。

Experimental study of grouting pile-soil interface and numerical simulation of bearing behavior of side-grouting uplift pile

The side-grouting uplift pile is a newly developed pile foundations. This paper aims to demonstrate the features of deformation and bearing capacity of this class of piles using experimental and numerical approaches. A series of large–scale direct shear tests were performed to show the effects of grouting on the behavior of pile-soil interface. Based on the experimental observations of the large-scale shear tests, the revised coulomb friction model is built and used in the finite element method. The bearing capacity and load-displacement curve for non-grouting and side-grouting piles are obtained respectively. The study results show that the side-grouting uplift pile possesses a larger skin-resistance because its deep critical skin-resistance can be fully developed. As a consequence, the side-grouting uplift pile displays a much higher bearing capacity than traditional uplift pile.