EFFECTS OF LIQUEFACTION ON BEARING CAPACITY AND SETTLEMENT OF SHALLOW FOUNDATION

Abstract

Liquefaction is a phenomenon in which the strength and stiffness of a soil is reduced by earthquake shaking or other rapid cyclic loading. Liquefaction and related phenomena have been responsible for huge amounts of damage in historical earthquakes around the world. Seismically induced settlement of buildings with shallow foundations on liquefiable soils has resulted in significant damage in recent earthquakes. Engineers still largely estimate seismic building settlement using procedures developed to calculate post liquefaction reconsolidation settlement in the free-field. Earthquake-induced excess pore pressure build-up and the associated shear strength degradation of liquefiable soils may result in bearing capacity degradation and seismic settlement accumulation of shallow foundations, two detrimental effects which need to be taken into account in order to ensure a viable shallow foundation design. Modeling of soil behavior is the main step in soil liquefaction prediction process. Nowadays, several constitutive models for sand have been presented. One of the most useful models in this term is UBC3D-PLM SAND model. In this research, the capability of this model is considered by using PLAXIS 2D software. In this study, a model is developed to study the effect of liquefaction on shallow foundation. Various parametric analysis were carried out by using this numerical simulation. Excess pore pressures, Excess pore pressure ratios, settlements and degraded bearing capacity are calculated and analysed.