Abstract
In order to minimize settlement of a shallow foundation, a model test is performed using geogrids for reinforcement. The optimal reinforcement is found by varying reinforcement length and changing reinforcement layer. From the test results, it is inferred that 2 layers and 4 times the foundation length is the most effective reinforcement condition obtained using geogrids. As a result of this tendency, 2 layers-4 times and 2 layers-5 times conditions are used to determine the reinforcement effect of two types of geogrids with the same tensile strength and of a single type of geogrid but with two tensile strengths. The reinforcement effect of the welded type is less than that of warp-knitted type. It can be seen that frictional resistance is developed at the soil-geogrid rib interface; therefore, the reinforcement capacity is reduced. It is inefficient to use reinforcement of high tensile strength under conditions of allowable bearing capacity, but it is necessary to choose reinforcement of suitable tensile strength under conditions of ultimate bearing capacity.