Seismic response of single piles in liquefiable soil considering P-delta effect

Abstract

Dynamic analyses of piles subjected to both vertical and horizontal loading under seismic conditions are of great significance to geotechnical and practicing engineers and the numerical methodology proposed in the present study fills the existing research gap. A finite difference based computer program FLAC3D is used to model a single pile and obtain the deflection and bending moment behaviour along the depth of the pile, under earthquake loading conditions in both non-liquefiable and liquefiable soil. The various earthquake motions considered in the current analysis includes 1989 Loma Gilroy, 1995 Kobe, 2001 Bhuj and 2011 Sikkim motions The bending moment is maximum at the interface of the liquefying and non-liquefying soil layers due to shear strain in the soil being discontinuous across the interface of the layers. The free field ground surface displacement is observed to initially increase with time, reaching the maximum at some instant during shaking and thereafter it remains constant with time, due to local failure of the liquefiable soil around the pile foundation. The combination of vertical load and lateral load on the pile top is varied to obtain the P-delta curves under dynamic loading conditions which are important factors for peak pile bending moment, when there is lateral spreading due to liquefaction causing displacement of the pile head, and inertial load from the superstructure is present. Hence a thorough evaluation of both horizontal and vertical inertial interactions and kinematic interactions due to free field motions, is necessary for considering the behaviour of piles in liquefiable soil and under combined loading situations.

Study on the Time Domain Semi Analytical Method for Horizontal Vibration of Pile in Saturated Clay

“…Nguyen [8] used numerical simulation methods to simulate the dynamic behavior of soil, pile foundations, and structures under seismic excitation while considering the seismic performance of buildings located on soft soil. Kaustav [9] used finite difference software to analyze the deflection and bending moment behavior along the pile length in non liquefied and liquefied soils under seismic loading conditions, and studied the horizontal and vertical inertial interactions as well as the kinematic interactions caused by free field motion. Kamel [10] used numerical simulation methods to study the response of adjacent pile foundations, strong grouting protection, and soil interactions induced by tunnel construction.…”

Response of soil–pile–superstructure–quay wall system to lateral displacement under horizontal and vertical earthquake excitations

“…In parallel to the experimental study, numerical methods have been used to investigate other influential factors on the SPSQ system with lateral displacement, such as internal friction angle, shear modulus, and hydraulic conductivity of soils, the elasticity and material nonlinearity of pile, the combined effect of kinematic load and inertial load, and the effectiveness of different mitigation strategies (Cubrinovski et al, 2008;Tasiopoulou et al, 2013;Tang et al, 2015;Li and Motamed, 2017;Su et al, 2018;Li et al, 2019;Chatterjee et al, 2019;Zhao et al, 2022). Particularly, Rajeswari and Sarkar (2021) reported that the vertical ground motion has no additional significant influence on the behavior of inclined pile groups embedded in the gently sloping ground which has been encountered with lateral displacement due to horizontal ground motion.…”

Effects of axial loading on dynamic response of laterally loaded single piles in liquefiable layered soil of Kolkata city considering nonlinearity of soil

“…IS 2911[47] recommends depth of fixity method which is based on bending failure mechanism for evaluating the flexural response of earthquake -induced laterally loaded pile foundations. The response of pile foundations in liquefiable soil considering both inertial and kinematic interaction effects have been studied by several investigators [48][49][50][51][52]. Recently, Bhattacharya [53], Knappett and Madabhusi [54] and Kimura and Tokimatsu [55] established an alternative theory of possible pile failure in liquefiable soil based on buckling mechanism.…”