An Investigation Of The Interaction Between A Laterally Loaded Pile And The Layered Transversely Isotropic Saturated Soil

In geotechnical engineering,the design of a foundation is much more critical than that of a superstructure.The moduli and permeability of the soil under the foundation vary considerably with each soil layer.Thus,when a soil stratum is not suitable for a shallow foundation system,pile foundation is used to reinforce the stratum of the weak soil to prevent excessive settlement of superstructures.Hence,in this study,the interaction between a single laterally loaded pile and the layered half-space soil is investigated.A numerical model for predicting the response of the laterally loaded pile embedded in the layered transversely isotropic saturated(TISS)soil is established.To this end,the pile-soil interaction problem is decoupled into an extended halfspace and a fictitious pile.Then,the corresponding fundamental solution resulting from the reflection and transmission matrix(RTM)method is combined with the fictitious pile method to establish the second kind of Fredholm integral equation for the loaded pile.The major contents of this paper are as follows:(1).The fundamental solution required to study the behavior of the single pile in the layered TISS is developed through the reflection and transmission matrix(RTM)method.Based on the Biot's theory,the partial differential equations for the TISS are formulated.Meanwhile,the Hankel-Laplace transformations are used to form the corresponding ordinary differential equations,which are solved to produce the solution as well as the transform matrix of the state and static wave vectors.Systematically,through the inverse Laplace transform,the time domain fundamental solution is retrieved.(2).The response of the pile in the half-space soil is thoroughly analyzed.To facilitate the analysis,Muki's pile method is adopted and combined with the fundamental solution of the layered TISS and the integral equation for the pile is establised.In accordance with the fictitious pile method,the Young's modulus of the fictitious pile is obtained by subtracting the elastic modulus of the soil from that of the real pile.Schapery's method is used to obtain the time domain integral equations of the second kind.1.A Fortran program is developed to yield the numerical results for the pile embedded in the layered TISS.To validate the proposed model,the results obtained here are compared with existing results,and an excellent agreement is observed between the two models,thus verifying the proposed model.In addition,parametric studies are undertaken to demonstrate the influence of the moduli and permeabilities of the soil on the behavior of the pile in the layered TISS.