This study was conducted to investigate the permanent settlement of a shallow square foundation in improving the cyclic load-settlement characteristics of reinforced sand. Also, The ultimate bearing capacity (UBC) for unreinforced sand and reinforced sand has been compared. The foundation was initially subjected to an allowable static load and the cyclic load was superimposed on it. Based on the model test results, the ultimate permanent settles is markedly reduced due to geogrid reinforcement.
Several laboratory model tests results are presently available which relate to the determination of permanent settlement of shallow foundation subjected to various types of dynamic loading. Cunny and Sloan (961), Shenkman and Mckee (1961). Jackson and Hahala (964) conducted several small-scale laboratory tests to observe the load-settlement relationships for shallow foundations supported by sand and clayey soils due to vertical transient loading. The transient loads to which the footings were subjected were of nature shown in Figure 1. The nature of settlement of footings with time during the application of the dynamic load is also shown in the same figure. In general, during the rise time (t,.) of the dynamic load, the settlement of a footing increases rapidly. Once the peck load [Qd(max)] is reached, the rate of settlement with time decreases. However, the total settlement of a footing continues to increase during the time of the load(tdw) and reaches a maximum value (Smax) at the end of dwell time. During the decay period of the load(tde), the footing rebounds to some degree. Raymond and komos(1978) have presented the results of the cyclic load amplitude and the related settlement of strip surface foundation supported by dense sand. In spite of these studies, there are several factors which control the permanent settlement of shallow foundations due to dynamic loading which have not yet been clearly identified.
