In practice

pile-soil-cushion interaction of composite grounds with piles is not well considered in bearing capacity and settlement estimation. To solve it

based on the relation among pile-soil-cushion

the differential equations of settlements of piles and soil in large-area pile groups together with their solutions are presented. Compared to the results of finite element analysis

these solutions are quite accurate. This method greatly enhances the speed of calculation. The parameters used in this method are all routine soil parameters and are easily obtained through soil test. Also

the stress dependency of both the soil-pile limit friction and the compression modulus is taken into account in the proposed method. This method is practical and applicable to calculate pile-soil stress ratio and settlement of composite grounds with piles.