中文摘要：

为了有效计算与分析软土地基中基桩的受力与位移情况,采用土体弹塑性三折线模型计算桩侧土体的摩阻力与桩土相对位移。考虑桩侧土体发生沉降时桩-土保持能量平衡,导出产生负摩阻力时基桩的能量平衡方程,进而给出不同位移条件下桩身轴力与位移的计算式。最后,运用该方法对某工程实例进行数值计算,计算结果与实测数据基本一致,证实了三折线模型的能量平衡计算式能够用于分析基桩在各级均布荷载作用下的受力特性。

英文摘要：

In order to effectively calculate and analyse the stress and strain of pile in soft soil foundation,soil elastoplastic three-phase segmented model is adopted to calculate the pile-soil relative displacement and skin friction.Considering that pile and soil keep energy balance when settlement of foundation soil occurred,an energy balance formulation of pile is deduced.Furthermore,formulas of pile-axial forces and shift in different pile-soil relative displacement condition are given.Finally,a numerical calculation of an engineering case was conducted and compared its results with in-situ data.It shows that the calculated results are basically consistent with the measured data.It verifies that the energy balance formula using three-phase segmented model can analyze the stress attributes of pile in uniform load.