砂土中微型桩p-y曲线研究

Analysis on p-y Curves of Micro-pile in Sand

本文通过砂土中微型桩侧向受荷室内足尺模型试验,获得了微型桩在侧向受荷时不同深度处桩身位移、弯矩和桩周土反力,研究了微型桩的变形和受力特性。在试验基础上,利用三维有限元方法建立了微型桩-土互相作用模型,针对桩径从0.1 m到0.2 m的微型桩p-y曲线进行分析,并与常用的Reese法和API法的进行比较,发现常用的Reese法和API规范的p-y曲线的初始刚度偏大及桩周土极限抗力偏小。最后,在试验及三维有限元模型的基础上研究了微型桩-土p-y曲线沿深度变化的分布特性,提出了适用于砂土中微型桩的双曲线型p-y曲线。

Full scale test of micro-pile under lateral load in sand is carried out using the hydraulic servo testing system. The lateral displacement,bending moment of the micro-pile and the soil-pile reaction at different depths were got to study the mechanical characteristics and deformation features of micro-pile. Based on the test results,the micropile and soil interaction model was built with 3 D finite element method and p-y curves for micro-pile in sand were calculated. The result indicates that the p-y curves of traditional Reese method and API method have relatively larger initial stiffness but smaller ultimate soil-pile resistance. Finally,the characteristics of p-y curves at different depths were studied and a hyperbolic p-y curve to compute micro-pile in sand was presented based on the tests and 3 D finite element model.