Bearing capacity of shallow foundation on geogrid reinforced soil

Abstract

An extensive laboratory test program was planned to satisfy the targets of this research which consists of studying the effect of depth of the first layer, number of reinforced layers, varies types of soils, and different shapes of foundations on performance of shallow foundations on geogrid soil reinforcement. This research included manufacturing a new test machine for measuring the bearing capacity (BC) of different types of foundations rested on different types of reinforcement soils. Three types of foundation was used: strip, rectangular and square foundation. The type of geogrid material was the biaxial geogrid. The research considered three types of soils: clayey soil, sandy and sandy underlain by silty clay soil. The results obtained through this study revealed an increase in the bearing capacity for specific values of design parameter. It is concluded that the depth of the first layer affects the results. When the depth of the first layer increases, the bearing capacity of foundation decreases. Optimum value of the ratio of first layer depth to the width of foundation (u/B) was about 0.33 for clayey soil and 0.25 for sandy soil. The influence depth of reinforcement layer (d/B) was 1.25 at silty clay and sandy soil. Optimum number of reinforcement layers about 3 for silty clay and sandy soil. For sandy soil, the bearing capacity ratio (BCR) increased with increasing the number of reinforcement layers in different proportions. For the shape of footing, the square footing showed a maximum value of bearing capacity of foundation on silty clay and sandy soil compared to other types of foundations.