3-Dimensional numerical modelling of geocell reinforced sand beds

Numerical modelling of the geocell has been always a big challenge due to its complex honeycomb structure. Generally, the equivalent composite approach is adopted to model the geocells. In equivalent composite approach, the geocell-soil composite is treated as the soil layer with improved strength and stiffness values. Though this approach is very simple, it is unrealistic to model geocells as the soil layer. This paper presents a more realistic modelling approach to model geocells in 3-dimensional (3D) framework. Numerical simulations have been carried by forming the actual 3D honeycomb shape of the geocells using the finite difference package FLAC3D (Fast Lagrangian Analysis of Continua in 3D). Geocells are modelled using the geogrid structural element available in the FLAC3D with the inclusion of the interface element. In addition to the modelling of geocells, other two cases, namely, only geogrid and geocell with additional basal geogrid cases were also modelled. It was found that the geocells distribute the load laterally and to a relatively shallow depth as compared to unreinforced case and the geogrid reinforced case. The numerical model was also validated with the experimental studies and the results are found to be in good agreement with each other. The validated numerical model was used to study the influence of various properties of the geocells on the performance of the reinforced foundation beds. The performance of the foundation bed was directly influenced by the modulus and the height of the geocells. Similarly, the pocket size of the geocell inversely affected the performance of the reinforced beds. The geocell with textured surface yielded better performance than the geocell with smooth surface.