考虑桩-土非线性接触的自平衡桩基测试有限元分析

Analysis of self-balance pile test based on finite element method considering pile-soil non-linear contact

自平衡桩基测试由于不受场地限制,在桥梁桩基检测和水上试桩领域得到较为广泛应用,但由于自身承受荷载机理、桩土相互作用与传统桩基静载测试不同,目前其实际应用仍然存在一些问题,因此需要在自平衡加载方式下建立合理数值模型来为进一步理论分析奠定模型基础。在考虑桩体非线性接触面基础上,研究了决定非线性接触性质的摩擦系数计算原则及相关模型参数取值,基于ANSYS接触面单元建立了自平衡桩基有限元模型,以武汉工程为依托,与实测结果进行对比,结果表明基于接触面单元建立的自平衡桩基模型具有更高的精确度,能够很好反映真实荷载作用下上下段桩位移曲线图。

The self-balance pile test has been widely used especially in pile foundation of a bridge and water pile foundation without space limitation, but there exists some shortcomings because of its own bear load mechanism characteristics. This paper examines the calculation and selection principle of friction coefficient which can decide the non-linear properties, considering non-linear interaction of pile-soil and developing the finite element model based on ANSYS contact element. Through a practical engineering case, the results with the finite element method are described. The results show that the finite element method has a higher accuracy and can truly reflect the curve of displacement of the top and bottom cells. An accurate model for the theory study of self-balance pile test is also provided.