Effect of Cavity on Bearing Capacity of Shallow Foundation in Reinforced Soil

Abstract

In this paper, effect of cavity on geogrid reinforced soil having cavity at certain depths are examined and analysis has been carried out for load bearing capacity and settlement of footing resting on geogrid reinforced surface. PLAXIS-2D (v8) finite element package has been used for which 15-noded a triangular element has been used. Outcomes obtained from the analytical study quite resemble with available literature results. A total of 52 cases has been analyzed to examine the impact of number of geogrid layers, spacing of subsequently layer, cavity location, size of the cavity 0.1B, 0.25B, and 0.5B and depth of footing for which M-C model is used to analyze the elastic failure. It can be observed that optimum depth of the first reinforcement bed was around 0.5 times footing breadth. Thus the optimum depth 0.5B was considered for different no of geogrid layers. The maximum improvement of load bearing capacity for reinforced without cavity of cohesive soil for N = 4 is 25.27% the percentage decrement of load bearing capacity for reinforcement with cavity size having diameter 0.1B, 0.25B, and 0.5B were 23.14%, 17.07% and 15.83% respectively. Due to this increasing diameter of cavity leads to observable decrease in the load carrying capacity of the foundation at constant depth of cavity to the footing breadth ratio.