Experimental investigation of flexible pile behavior under lateral cyclic and post cyclic loading in sandy soil

Document Type : Research Article


School of Engineering, Shiraz University, Shiraz, Iran


Lateral behavior of piles is one of the most challenging design issues. While previous studies have mainly focused on rigid piles, a little attention has been paid to flexible ones. In this study, the behavior of flexible piles under lateral cyclic loading is investigated by experimental tests. For this purpose, a device was designed and commissioned for cyclic loading tests which can generate different types of sinusoidal loads. Measurement was made on the load and displacements during the cyclic loading with a loadcell and Linear Variable Differential Transducer (LVDT). The role of key parameters in cyclic loading including such as the frequency, loading interval, number of cycles, cyclic loading direction and also soil density were investigated. Moreover, post cyclic loading tests were performed to evaluate piles lateral bearing capacity. Experimental observations showed that under one way and two way loadings, the stiffness gradually increases during 100 cycles of loading while under one way without complete unloading process, the stiffness starts to decrease and then remains constant. Increasing the frequency from 0.1Hz to 0.2Hz has shown a significant effect in increasing the lateral cyclic resistance. Under the one way loading, the residual force at the pile head increases with increasing the cyclic loading interval.


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