NUMERICAL ANALYSIS OF SETTLEMENT, AND STRESS CONCENTRATION RATIO IN CLAYEY SOILS REINFORCED BY FLOATING SINGLE AGGREGATE PIERS

This study discusses the results of numerical modeling aspect of aggregate pier foundations (aggregate piers) in soft, compressible soils. FLAC 2D (Fast Lagrangian Analysis of Continua), a finite difference code is utilized in the analyses. Use of axisymmetry enabled to visualize a three dimensional model throughout this research. The primary objective of this research is to make comparisons for stress concentration ratio ‘n ’ , and settlement reduction ratio b for given variables consisting of length, diameter, elastic modulus of the aggregate piers, and foundation pressures. Analyses have been carried out with 1, 1.5, 2, and 3 m long piers with diameters of 60 cm, and 80 cm, placed under a circular footing in 1.30 m diameter. Two values for elastic modulus of the piers have been used to reflect the effect of pier stiffness on settlement behavior. Analysis and design methodology have been carried out in three stages. The first ii stage consists of modeling the matrix soil with an elastic constitutive model and exerting foundation pressures to first check the accuracy of the mesh by comparing the effective vertical stress and settlement values by analytical methods. Once satisfactory results ar