Study on the Dynamic Soil-Pile-Structure Interactive Behavior in Liquefiable Sand by 3D Numerical Simulation

Abstract

The dynamic behavior of structures in liquefiable sand exhibits more complicated characteristics, due to the development of excess pore pressure caused by cyclic loading, than that in dry sand. Therefore, it is crucial to accurately predict the soil-pile structure behavior during liquefaction to prevent damage to the structures. In this study, three-dimensional numerical modeling was performed to predict the dynamic soil-pile behavior during liquefaction. To directly simulate pore pressure generation due to soil shear deformation, the Finn liquefaction model was applied and coupled with the Mohr-Coulomb elasto-plastic model. Soil nonlinearity was considered by applying hysteretic damping, and the interface model was applied to simulate various dynamic phenomena between the soil and pile. Simplified continuum modeling was introduced to prevent reflection wave generation and increase analysis efficiency. The applicability of the proposed numerical model was validated using the experimental results. Thereafter, a parametric study was conducted to provide a better understanding of the dynamic behavior of pile foundation during liquefaction. From a series of parametric studies, several important factors that can affect the dynamic pile responses in liquefiable sand were identified. Also, the characteristics of the dynamic soil-pile structure interactive behavior, which are significantly different from each other in liquefied and dry sand, were analyzed qualitatively and quantitatively.

A Study on the Dynamic Behavior of a Vertical Tunnel Shaft Embedded in Liquefiable Ground during Earthquakes

“…The Finn model was incorporated into the Mohr-Coulomb plasticity model. For practical purposes, Byrne [27] proposed simple equations to determine these parameters as functions of the relative density of sand, as shown in Equations (1) and (2):…”

“…An interface element that allows both slippage and separation between the soil and the shaft structure under strong earthquake loading was applied to simulate the dynamic soil-structure interaction. The interface model attaches normal and shear springs with equivalent spring stiffness between the soil and shaft, as shown in Equation 7 [1]. In Equation (7), G reflects the nonlinear reduction in the soil shear stiffness; therefore, the nonlinear behavior at the interface can also be captured in the proposed model.…”

“…As a result, public concern regarding the seismic stability of major infrastructure has been increasing, and revision of the seismic design criteria for various facilities is in progress. As summarized in Kwon & Yoo (2020) [1], behavior of the soil-pile system in in liquefiable sand exhibits more complicated characteristics than that in dry soil due to the development of excess pore pressure caused by cyclic loading. Once earthquake occurs, the seismic wave originating from the bedrock causes cyclic underground shear stress as it is propagated to the upper soil.…”

Research on Shear Behavior of Sand–Structure Interface Based on Monotonic and Cyclic Tests

“…The problem of the interaction between soil and structure is widespread in geotechnical engineering [1][2][3][4][5][6][7][8][9], such as the interaction between piles and surrounding soil, underground diaphragm wall and soil behind the wall, etc. Due to the great difference between the stiffness of soil and structure, under the action of external load, discontinuous phenomena such as shear slippage, dislocation and disengagement may occur at the contact surface.…”

Stationary Dynamic Response of a Circular Rigid Foundation Partially Supported by a Flexible Pile and Interacting With a Half-Space

“…A dynamic analysis of pile and raft responses to seismic loads in which the piles are not rigidly connected to the raft was presented by Saadatinezhad et al (2019). More recently Kwon and Yoo (2020) presented a study on the dynamic response of piles interacting with liquefiable soils, showing that this is very actual research topic.…”