Generalized Model for Geosynthetic-Reinforced Granular Fill-Soft Soil with Stone Columns

This paper pertains to the development of a mechanical model to predict the behavior of a geosynthetic-reinforced granular fill over soft soil improved with stone columns. The saturated soft soil has been idealized by Kelvin — Voight model to represent its consolidation behavior. The stone columns are idealized by stiffer springs. Pasternak shear layer and rough elastic membrane represent the granular fill and geosynthetic reinforcement layer, respectively. The nonlinear behavior of the granular fill and the soft soil is considered. Effect of consolidation of the soft soil due to inclusion of the stone columns has also been included in the model. Plane strain conditions are considered for the loading and reinforced foundation soil system. An iterative finite difference scheme is applied for obtaining the solution, and results are presented in nondimensional form. Comparison between the results from the present study and the analytical solution using theory of elasticity shows reasonable agreement. The advantage of using geosynthetic reinforcement is highlighted. Results indicate that inclusion of the geosynthetic layer effectively reduces the settlement. Nonlinearity in the behavior of the soft soil and the granular fill is reduced due to the use of geosynthetic reinforcement layer.