Abstract
The behavior of clay subjected to repeated loading is an important foundation design consideration not only for structures which must resist seismic forces but also for other kinds of construction which must be capable of withstanding cyclic or intermittent loadings -such as pavements, storage facilities and off-shore structures. Clay samples under repeated loading are more compressible than those under static loading. The difference in compressibility or settlement between these two loading patterns seems to be due to secondary compression. The settlement of samples under repeated loading is caused and governed primarily by the magnitude of total load, the number of load cycles, the loading period, the load increment ratio, loading pattern and artificial cementation of the sample.This paper investigates the mechanism of consolidation of clay under repeated loading by means of considering these influencing factors. In particular, emphasis is placed upon the importance of secondary compression in consolidation under repeated loading rather than in consolidation under sustained (static) loading, because the predominant settlement in repeated loading must be ascribed to secondary compression. The proposed method of analysis is a combination of two methods ; a method which takes the effect of secondary compression into consideration is combined with a modified version of Terzaghi's theory for repeated consolidation of clay. The calculated settlement under repeated consolidation is compared to the observed settlement in repeated consolidation tests on clay samples.
