Kinematic Response of Pile Foundations in Liquefiable Soil of Indo-Gangetic Basin During Earthquake

Abstract

Indo-Gangetic Basin (IGB) lying toward south of the Himalayas formed of deep alluvial layers is tectonically very active. It experienced some great earthquakes in past and signs of liquefaction had been reported by previous researchers. Understanding of deep alluvial deposit impact and liquefaction phenomena on response of pile foundations under seismic loading is of immense importance. This paper presents linear as well as nonlinear analyses of pile foundations of approach viaduct of a rail–road bridge near Patna situated in the liqueafiable soil of IGB. The above study was based on the parameters obtained from both field and laboratory tests. Six synthetic earthquakes of different magnitudes and peak ground acceleration were considered. A comprehensive state-of-the-art approach of determining kinematic response of pile foundation (considering liquefaction) using finite element method has been presented. A series of analyses were conducted such as free field ground response analysis, eigenvalue analysis for finding modes of vibration and dynamic linear and nonlinear time history analysis using HHT-α (Hilber, Hughes and Taylor) implicit direct method. Mohr–Coulomb criteria and UBCSAND model were used in this analysis. In linear analysis, liquefaction could not be simulated. However, in nonlinear analysis it could be done successfully, because the dynamic nonlinear analysis method has capability to perform investigation in the required strain range of liquefaction and lateral spreading.