Laboratory investigation of behavior of foundations on geosynthetic-reinforced clayey soil

The behavior of foundations on geosynthetic-reinforced clayey soil of low to medium plasticity using laboratory model footing tests was investigated. The model footing was made of a steel plate with dimensions of 152 mm (6 in.) x 152 mm (6 in.). The parameters investigated in this study included the top layer spacing, the number of reinforcement layers, the vertical spacing between layers, and the stiffness and type of reinforcement. The effect of reinforcement on the vertical stress distribution in the clay and the strain distribution along the reinforcement were also investigated. The test results showed that the inclusion of reinforcement could significantly improve the soil's bearing capacity and reduce the footing settlement. With three or more layers of reinforcement, the settlement could be reduced by approximately 50% at a relatively medium surface pressure. The geogrids with higher stiffness performed better than geogrids with lower stiffness. The test results also showed that the induced vertical stresses in clay under the center of footing could be appreciably reduced with the inclusion of reinforcement, which would result in reducing the consolidation settlement. Insignificant strain measured in the geogrid beyond its effective length of 6.0B (where B is the footing width) indicated that the geogrid beyond this length provided negligible reinforcement effect.