考虑桩端刺入沉降的桩土自平衡式复合地基设计

复合地基的本质是增强体与地基土通过变形协调共同承担上覆荷载。褥垫层的设置起到了协调桩土变形的作用，但褥垫层工作性状及变形特性尚不明确，其厚度设计仍然参考规范依靠经验判断，往往不能充分发挥地基土的承载作用。目前复合地基设计通常采用褥垫层调节桩土变形，而忽略了桩端刺入沉降协调桩土变形来发挥地基土的承载作用，为了利用桩端刺入沉降协调桩土变形，充分发挥桩间土承载的作用，减薄褥垫层或不设褥垫层并减小设计桩长，以期降低地基处理费用，实现桩土共同承担荷载的目的，建立了通过控制桩端刺入沉降协调桩土变形的自平衡式复合地基设计方法。通过与褥垫层方法对比以及工程实例计算，结果表明，该方法可更好地发挥桩土承载作用，为复合地基优化设计提供参考。

Pile-soil self-balanced composite foundation design considering pile-end piercing settlement

The nature of composite foundation is the load from the overlying shared by the reinforcement and ground soil via the deformation compatibility.Cushion plays a coordinating role of pile-soil deformation;however,its characteristics of the work and deformation characteristics are not yet clear.Designing cushion thickness still depends on experience or reference standard.It can not fully play the bearing capacity of foundation soil.The pile-soil deformation is usually adjusted by cushion in current composite foundation design.The pile-end piercing settlement coordinates pile-soil deformation and plays the role of foundation soil bearing capacity is ignored.Using pile-end piercing settlement to adjusted pile-soil deformation and bring foundation soil bearing capacity into full play,the cushion thickness is reduced or not to set cushion,and the designed pile length is shortened in order to reduce the cost of ground handling and achieve the purpose of load shared by pile and soil finally.A design method for pile-soil self-balanced composite foundation is established through controlling pile-soil deformations adjusted by pile piercing settlement.Through contrasting with the cushion method and project examples,it is proved that the method can show the foundation soil bearing capacity better,and provide references for the optimal design of composite foundation.