Calculation for Pile-soil Stress Ratio of Pile-net Composite Foundation under Embankment

DOI：

 作者 单位 蒋德松，张承富，赵明华，杨超炜 （湖南大学 土木工程学院，湖南 长沙 410082）

针对“路堤-加筋垫层-复合桩基”共同作用模型所存在的不足，从土拱、筋材变形以及桩土荷载传递三个方面对其进行改进.首先，考虑地基分层、埋深与上覆荷载对桩土荷载传递的影响，推导桩、土竖向变形函数.然后，引入沉降主控的筋材拉膜效应经验模型，考虑路堤与地基侧向变形对筋材拉力的影响.最后，在土柱模型的基础上，考虑相对位移量对界面摩阻力发挥的影响，推导路堤底部荷载分配与差异沉降的关系.在上述工作的基础上，以桩土沉降与荷载分配为等量关系，建立了改进后的路堤、筋材、桩体、桩间土共同作用模型，并得到了路堤下桩网复合地基的桩土应力比计算方法.通过工程实例对本文方法进行验证，证明了本文方法的合理性.

This paper focused on the improvement of the current pile-supported embankment calculation model from three aspects: soil arching effect，geotextile deformation and pile-soil load transfer due to the deficiency of the embankment- reinforcement- composite pile foundation interaction model. Firstly，considering the influence of foundation stratification, buried depth and overlying load on pile-soil load transfer，the vertical deformation function of pile and soil was derived. Secondly, the empirical model of the membrane effect was introduced to analyze the influence of the lateral deformation of the embankment and the foundation on the tensile force of the geotextile. Finally, based on the soil column model, this paper analyzed the relationship between load distribution and differential settlement at the bottom of the embankment in consideration of the influence of relative displacement on the interface friction. On the basis of the above work, the improved model of embankment, geotextile, pile and inter-pile soil interaction was established on the premise of the equal relationship between pile-soil settlement and load distribution，from which the calculation method was deduced of pile-soil stress ratio of pile-net composite foundation under the embankment. The rationality of the method mentioned was validated by practicable engineering examples.