Laboratory model test results on the ultimate bearing capacity of ∼ surface strip foundation supported by a nearly saturated clayey sot! reinforced with layers of geogrid are presented. The optimum values. for the width of reinforcement layers, depth of reinforcement and location of the first layer of geogrid for mobilization of maximum bearing capacity were determined. Based on the model test results, an empirical procedure to estimate the ultimate bearing capacity of strip foundations on geogrid-reinforced clay was developed.
During the last fifteen years or so, a number of small-scale. laboratory model test results were published which substantiate that the ultimate and allowable bearing capacities of shallow foundation can be increased by using single or multilayer(s) of geogrid as reinforcement in the soil located below the foundation. These studies were conducted primarily in sand (e.g., Guido et al., 1986; Khing et al., 1993; Yetimoglu et al., 1994). The studies were essentially carried out to evaluate the following parameters, in a nondimensional form, where the most beneficial effect will be derived from the reinforced soil with respect to the ultimate bearing capacity (Fig. 1): (Equations are shown in the paper) A review of the existing literature shows that, unlike the bearing capacity studies on reinforced sand, theoretical and!0r experimental studies relating to the ultimate and allowable bearing capacities of shallow foundations supported by geogrid-reinforced saturated clayey soil are practically nonexistent. Limited data on the topic of geosynthetic-reinforced clay can be found in the works of Ingold and Miller (1982), Milligan and Love (1984) and Dawson and Lee (1988). This paper reports the results of some recent laboratory model tests conducted to determine the ultimate bearing capacity of a surface strip foundation supported by geogrid-reinforced saturated clay.
