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为了考虑柔性基础下复合地基桩-土相对滑移特性和桩间土竖向应力变化对其沉降计算的影响,在分析复合地基沉降变形机理基础上,根据桩-土界面剪切变形特性,假定桩-土界面剪应力和剪切相对位移关系服从理想弹塑性模型,并将复合地基沉降视为由塑性区、弹性区和下卧层压缩变形区3个部分组成;根据塑性区桩-土界面剪应力与相对位移的关系特性,通过分析桩与桩间土竖向应力,建立塑性区压缩量分析方法;针对桩间土竖向应力变化特征,在对现有桩间土竖向位移模式进行改进的基础上,建立了考虑桩间土竖向应力变化和桩-土相对位移的弹性区压缩量计算模型,并采用已有复合地基下卧层压缩量分析方法计算下卧层的压缩量,从而建立柔性基础下复合地基沉降计算新方法。研究结果表明:该方法可反映桩-土相对滑移和桩间土竖向应力变化对沉降的影响;通过工程实例计算与其他同类方法进行对比分析,表明该方法合理、可行。
In order to consider the effect of pile-soil relative slipperformance and pile-soil vertical stress on settlement calculation of composite foundation under flexible foundation, based on the analysis of settlement deformation mechanism of composite foundation, according to the shear deformation characteristics of pile-soil interface, The relationship between shear stress and shear relative displacement at the pile-soil interface obeys the ideal elastic-plastic model and the settlement of the composite foundation is considered to be composed of three parts, the plastic zone, the elastic zone and the compressive deformation zone of the subsoil. According to the plastic zone pile-soil interface Shear stress and relative displacement. By analyzing the vertical stress between soil and pile, the analysis method of plastic zone compression is established. According to the characteristics of soil vertical stress change, Based on the improved model, the calculation model of elastic region compression considering the vertical soil stress change and the relative displacement of pile-soil is established. The compression of the subsoil is calculated by the compression analysis of the subsoil of existing composite foundation. So as to establish a new method of composite foundation settlement calculation under flexible foundation. The results show that this method can reflect the influence of the relative slip of pile-soil and the vertical soil stress on the settlement, and the comparison with other similar methods through engineering example shows that the method is reasonable and feasible.