Non-linear response of geocell reinforced dense granular layer over weak soil under circular loading

Abstract

A modified Pasternak model has been proposed to predict the behavior of a circular footing resting on a geocell reinforced granular layer overlying soft soil. In this model, the geocell reinforced granular layer was considered as a Pasternak shear layer and the soft soil as a series of Winkler springs to predict the overall behavior. Both linear and non-linear responses of the geocell reinforced bed were considered in the analysis, which correspond to low- (≤1% of footing width) and high-footing settlements (>1% of footing diameter), respectively. An iterative finite difference scheme is employed for obtaining the solution for the governing differential equations and the results presented in non-dimensional form. Results from the present model were validated with independent experimental test data by comparing the load-deformation responses. The model parameters, inverse of normalized shear stiffness of the geocell (α2) and the inverse of normalized ultimate bearing capacity (μ), were varied for the parametric study. It was found that the shear stiffness of the reinforced granular bed, i.e. the product of shear modulus and height of the geocell in a granular bed, plays an important role in improving the performance of the reinforced bed. Design charts were presented in the form of improvement factors for practical range of shear layer width, shear stiffness of the geocell reinforcement, and ultimate bearing capacity of the soft soil.