(1. Southwest Jiaotong University, Chengdu, Sichuan 610031, China; 2. The Third Railway Survey and Design Institute Group Corporation,Tianjin 300251,China)
Abstract:Research purposes : Rigid pile foundation is usually applied in high - speed railway foundation treatment in the soft soil area. However,the analytical calculation of composite foundation settlement which considering pile and soil common working mechanisms,is still far behind the actual requirement. In this paper, load transfer process between pile and soil is described by the related theory. And the distribution formulas of additional stress induced by soil surface load are fitted through the least squares method. Finally the analytical model for rigid pile reinforced zone can be established,which can meet the requirement of settlement calculation and design for rigid pile composite foundation.
Research conclusions: ( 1 ) Load transfer phenomenon is exactly existed between rigid pile and the adjacent soil. The positive and negative friction appears respectively. (2) Additive soil stress induced by soil surface loading is of nonlinear distribution in depth, and can be fitted by parabolic equation through the least squares method. (3 ) Settlement calculation of Beijing - shanghai high - speed railway foundation is close to the monitoring data,and the error is about 15%. (4) The calculated differential settlement between pile and soil is larger than the actual one if the pile skin and toe stiffness coefficients were determined by Randolph theory,so it is necessary to do further researches on the method of stiffness coefficients determination.