Evaluation of Dynamic Soil-Pile-Structure Interactive Behavior in Dry Sand by 3D Numerical Simulation

Abstract

A 3D numerical model based on finite-difference approximation was formulated to predict the dynamic soil-pile-structure interaction (SPSI) in dry sand. A non-linear elastic, Mohr–Coulomb plastic soil-constitutive model was adopted for the proposed methodology with a hysteretic damping model which can simulate nonlinear behavior of soil and an interface model which can predict separation and slippage between soil and pile according to the external load condition. Simplified continuum model was used to properly simulate the semi-infinite boundary and improve analysis efficiency. The proposed numerical model was validated by comparison with experimental results performed by Yoo (2013). Thereafter, a parametric study was also carried out to investigate the complex dynamic behavior of pile foundation under varying conditions. It was demonstrated that inertial force induced by superstructure is dominant for dynamic SPSI in dry sand whereas the kinematic force induced by soil deformation is relatively insignificant. Pile peak bending moment occurs at 30% of the pile length when pile length is no longer than 5 T and at about 30% of 5 T (1.6 T) when the pile length is longer than 5 T. The pile head fixity governed the peak bending moment profile of pile and affected the dynamic responses of the system in conjunction with other factors, such as pile rigidity.

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

“…Soil nonlinearity significantly influences the dynamic behavior of a pile and superstructure. If a simple elastic or elasto-plastic model as Mohr-Coulomb criteria is employed, implementation of an additional damping is necessary to properly represent the hysteretic characteristics (Han & Hart (2006) [28], Miglio et al (2008) [29], Kim et al (2012) [30], Cheng et al (2013) [31], Kwon & Yoo (2019) [23]). In this study, the hysteretic damping model was applied to consider both the nonlinearly varying soil modulus and energy dissipation.…”

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

“…where M t is the tangent modulus, L is the logarithmic strain, and L 1 and L 2 and are the extreme values of L. L 1 and L 2 represent the degradation rate and starting point of the degradation of G/G max curve, respectively. L 1 and L 2 for the model soil were set as −3.65 and 0.5, respectively, as proposed by Kwon and Yoo [28]. The maximum shear modulus of the soil, G max , was calculated using Equation (6), as proposed by Hardin and Drnevich [29].…”

“…where F(e) = 1/(0.3 + 0.7e 2 ), in which e is the void ratio; σ m is the mean principal effective stress; P a is the atmospheric pressure; k is the overconsolidation ratio exponent (which is equal to 0 in sand); and A and n are empirical coefficients, which were determined to have values of 247.73 and 0.567, respectively, for model soil [28]. 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.…”

Development of a Seismic Detection Technology for High-Speed Trains Using Signal Analysis Techniques

“…MyShake has been evaluated to be superior to ShakeAlert ( )—an earthquake early warning system in the western United States—in terms of both speed and accuracy [ 15 , 16 , 17 ]. Additionally, the Pacific Gas and Electric Company (PG&E) is pursuing a project to build a dense seismic observation network by attaching accelerometers to more than 300,000 gas and electricity meters in the Bay Area of the western United States [ 18 ]. The investigation of earthquake early warning systems has been an international effort.…”