中文摘要：

基于目前对带垫层的复合地基桩土应力比计算理论的研究不够完善和为了满足工程实际中桩土应力比计算的需要,从单元变形模式出发,综合考虑桩体的负摩擦阻力、桩顶刺入垫层和桩端刺入持力层的情况,并将土层按等沉面的位置分为上下两层土体,采用简化和收敛的方法,导出带垫层的CFG桩复合地基桩土应力比的计算公式。运用该方法对桩长为6.8-7.6 m的CFG桩复合地基进行计算得到的等沉面位置位于距桩底0.6-0.7的桩长处,应力比值在14-19。计算值与现场试验结果吻合较好,说明该计算方法能满足实际工程计算的需要,适用于刚性桩复合地基的桩土应力比计算。运用该分析方法对桩土应力比影响因素的分析表明：选择合理的桩间距、桩径、桩长和垫层材料能充分发挥CFG桩复合地基的承载能力。

英文摘要：

In view of the present situation that the theoretical research for CFG pile composite foundation with cushion is not perfect and the necessity which would satisfy the calculation of pile-soil stress ratio in engineering practice, based on the deformation mode of the pile unit, and by comprehensively taking the negative friction of pile, the conditions that the top of pile piercing into cushion and the bottom of pile piercing into underlayer into full consideration, the formula of pile-soil stress ratio of CFG pile composite foundation with cushion has been deduced under the assumption that the soil layer is divided into two layers according to the location of equal settlement section. Meanwhile, the simplification and convergence method have been adopted in the course of deducing the formula to obtain the location of the equal settlement section of a CFG pile composite foundation with the pile length as 6.8-7.6 m, which approximately located at the section that 0.6-0.7 length from the bottom of the pile and the value of stress ratio ranging from 14-19. By comparing the calculation value and the test result, it shows a good agreement with the engineering practice. Therefore, the results show that the proposed method is suitable for calculating the pile-soil stress ratio of rigid pile composition foundation. The analysis results of the influencing factors of pile-soil stress ratio adopting this method show that choosing the reasonable pile diameter, cushion materials, spacing and length of pile can give full play to the carrying capacity of CFG pile composition foundation.