Abstract: Considering the yield characters of foundation soil, the soil surrounding pile shaft is divided into elastic and plastic deformation zones. Based on the beam-on-foundation method the deflection curves differential equations of elastic and plastic zones of pile shaft are established respectively assuming that the coefficient of subgrade reaction is the three-parametric general form and the effect and effects such as gravity of pile, skin friction of pile are all taken into account. During the process of solving the differential equations, matrix transfer method with Laplace forward transformation and Laplace inverse transformation has been used to solve the deformation and internal force for axially and laterally loaded piles. And then, the computational procedure is compiled using the Fortran language. Finally, this approach is verified by the data from experiment. The results indicate that the computed data and test data are in good agreement; and then, the discreteness of inversion parameters of three-parametric subgrade reaction is very small, meaning that the presented approach is applicable in engineering practice.

Key words: yield of soil, coefficient of subgrade reaction, axially and laterally loaded piles, matrix transfer method