Dynamic Lateral Response of the Partially-Embedded Single Piles in Layered Soil

Abstract

Scouring can reduce the strength and rigidity of the pile–soil system and become one of the major causes for the failure of the structure of the partially-embedded single pile. The stratification of the soil fields has a significant influence on the internal force and deformation of laterally-loaded piles. A dynamic model of the laterally-loaded single pile in layered soil is established employing Hamilton’s principle based on the modified Vlasov foundation model. Then, the finite difference method is used to obtain the numerical matrix containing the control equations of the single pile to achieve accurate modeling of the soil–structure interaction (SSI) system affected by scouring, so as to solve the natural frequencies of the single pile. Green’s function method obtains the analytical solution of the forced vibration of the single pile. The effects of scouring and the layered soil on the dynamic response of the single pile are studied by numerical calculation and parameter analysis. It is shown that the dynamic model of the partially-embedded single pile in layered soil based on the modified Vlasov foundation model can accurately predict the dynamic characteristics of pile foundation affected by scouring. As the scouring degree intensifies, the first-order natural frequencies of the single pile in layered soil decrease significantly. The subgrade reaction coefficient of each layer of soil in the modified Vlasov foundation model decreases, and the shear coefficient increases. The first-order natural frequencies of the single pile at each scour level increase with the increase in the thickness of the underlying soil. When the elastic modulus of the first layer of soil is increased by one time, the first-order natural frequencies of the single pile are increased by about 20%.

An Investigation into the Lateral Bearing Performance of a Single Pile Embedded at a Three-Dimensional Asymmetric Local Scour Site Using the Modified Strain Wedge Model

“…Under three-dimensional asymmetric local scour conditions, the calculation of vertical effective stress in the soil around the pile is divided into two parts: first, the vertical effective stress generated via the soil below the bottom of the scour hole, and second, the additional stress generated via the soil above the bottom of the scour hole. These are determined via segmental double integration in the x and y directions using Equation (12), with each component shown below:…”

“…In current pile design practices, the local scour effect is typically addressed by removing the sediment layer within the local scour depth range when analyzing the lateral response of the pile. However, the contribution of the sediments surrounding the pile is often disregarded in this process [11,12]. If the soil layer is completely scoured to the scour depth, the pile's side resistance will be significantly reduced compared to considering the geometry of the scour hole.…”

Seismic Response Analysis of Anchor Joint in Shield–Driven Tunnel Considering Soil–Structure Interaction

“…It is well known that the SSI effect has a significant influence on the static and dynamic response of the structures [10][11][12]. Thus, the SSI effect should be properly taken into account to obtain satisfactory results.…”