Abstract: The mechanical behavior of the pile foundation under retaining wall is complicated due to the influence by multi-layer of soils. Previous studies have not considered the effects of soil layers on the internal force and displacement of laterally loaded piles. Therefore, the bottom of the pile under the cap requires to enter the rock together with the characteristics of the poor upper soils and strong lower strata. The soil underneath the pile cap could be divided into “soft” soil stratum, “hard” soil layer, and bedrock. Considering the influence of the force transmitted by the superstructure on the pile shaft, the pile can be simulated as an elastic beam placed vertically in the soil. The corresponding differential equation is established for different soil layers and different locations. The continuity and boundary conditions are analyzed to estimate the deflection, rotation angle, shear force, and bending moment of different soil layers. The condition degradation is performed to verify the scientific nature of the analysis. Combining engineering examples to verify the scientific nature of the numerical results, it has been proven that the pile shaft with the maximum force below the soil layer boundary. The conclusions obtained can provide reference for the design of pile supported foundation support beams and retaining walls.

Key words: Piled Foundation, Single Row Pile, Beam on Elastic Foundation, Internal Force Calculation, Power Series