（1 浙江大学岩土工程研究所  杭州 310027；2 西安建筑科技大学土木工程学院  710055）
［提要］  根据竖向荷载作用下桩的变形特征，将桩身变形表示为含有待定参数的多项式。基于最小势能原理，推导了基桩抗压刚度计算公式，分析了不同地基土层情况下基桩抗压刚度的变化规律及其影响因素。结果表明，桩长径比、桩土相对刚度对抗压刚度有较大的影响，土层厚度与桩长之比对抗压刚度的影响较小，土层分布不同，桩抗压刚度表现出不同的变化规律。
［关键词］  基桩抗压刚度  最小势能原理  半无限  有限厚度  均匀地基  多层地基
Calculation of Pile Compressive Stiffness Based on Principle of Minimum Potential Energy/Cao Weiping1，2, Chen Yunmin1(1 Institute of Geotechnical Engineering, Zhejiang University,Hangzhou  310027,China; 2 College of Civil Engineering,Xi'an Univ.of Arch.& Tech.,Xi'an 710055,China)
Abstract:The pile compressive stiffness is formulated based on the principle of minimum potential energy. Further study on the effects of pile lengthradius ratio, pilesoil stiffness ratio and soil depth to pile length ratio on pile compressive stiffness is carried out. The results show that pile compressive stiffness is significantly affected by pile lengthradius ratio, pilesoil stiffness ratio and  different soils display, while soil depth to pile length ratio has less effect.
Keywords:pile; compressive stiffness；  energy method； semiinfinite； finitedepth; homogeneous soils； multilayered soils