Effect of cyclic loading frequency on cyclic behaviour of saturated sand

Abstract

In practical engineering, sand fill or sediments subjected to cyclic loadings at varying frequencies due to earthquakes, traffic, and waves may cause complex soil responses. To investigate the effect of loading frequency on the cyclic behaviour of saturated sand, a series of undrained cyclic torsional shear tests covering a wide range of loading frequencies were conducted on Fujian sand. The excess pore water pressure (EPWP) in saturated sand can be divided into two components: residual and transient. Special focus was on the effect of loading frequency on the development of residual EPWP, transient EPWP, and shear strain amplitude. The key finding demonstrates that the loading frequency has a considerable effect on the association between the double amplitude of transient EPWP and shear strain amplitude. Based on the test data, a threshold strain is proposed that can be used to predict the onset of shear dilatancy in saturated sand. The liquefaction strength in the cyclic torsional shear tests was also investigated and was found to be significantly influenced by the loading frequency. The cyclic resistance ratio (CRR15) of saturated sand shows an increasing trend with the increase in loading frequency.