Bearing capacity of geosynthetic reinforced sand bed on problematic soil

The paper presents analysis to find out the bearing capacity of strip footing resting on geosynthetic (geogrid/geotextile) reinforced sand bed overlying non-homogeneous clay. The model considered for the study consists of sand bed overlying soft non-homogeneous clay, whose undrained shear strength increases linearly with depth. As most naturally deposited clays have induced non-homogeneity, thereby effective stress and hence the undrained shear strength increases with depth. A single layer of geosynthetic reinforcement is placed in the sand bed to study the effect of reinforcement. To arrive at the ultimate bearing capacity of the double layered foundation system, Meyerhof's punching mode of failure for footings on dense sand (with/without reinforcement) overlying soft non-homogeneous clay is extended to include the non-homogeneity of soft clay, shear resistance of sand fill and axial resistance of the reinforcement. Analytical solutions are developed for strip footings supported on geotextile/geogrid reinforced sand beds. The predicted bearing capacity values are found to compare well with some of the available experimental values. A parametric study quantifies the effect of various parameters on the bearing capacity.