Evaluation of Dynamic Properties of Partially Saturated Sands Using Cyclic Triaxial Tests

Abstract

A series of strain-controlled cyclic triaxial tests were conducted to estimate the dynamic properties and the cyclic behaviour of partially saturated synthetic fine- and medium-grained sand. The soil samples were prepared for the cyclic triaxial test at low (RD ≤ 20%) and high relative density (RD ≥ 60%). The test results of fine- and medium-grained sand revealed that both shear modulus and damping ratio reduces with the increase in the initial degree of saturation (expressed in terms of Skempton’s coefficient B). The maximum excess pore water pressure (EPWP) ratio development at initial cycles follows an increasing trend with the increase in the B coefficient. The studied fine sand is found to be affected more by the initial degree of saturation due to more voids present in it. Another novel aspect documented here is the effect of initial soil saturation on the Dobry’s EPWP model parameter F. The model parameter F has been modified depending on the initial degree of saturation, relative density and grain size of the soil sample.