Experimental Study on Dynamic Shear Modulus of Saturated Sands under Complex Initial Stress States

摘要

A series of cyclic undrained torsional tests on Fujian standard sand isrnconducted using a newly developed hollow cylinder shear apparatus,rnaimed at clarifying the influence of complex initial stress states onrndynamic shear modulus characteristics of saturated sands. The effect ofrnexcess pore water pressure generated during undrained cyclic loadingrnon stress-dependent shear modulus is also properly evaluated. The testrnresults show that dynamic shear modulus of tested sands are stronglyrnaffected by complex initial stress states. Nevertheless, the introductionrnof reference strain to normalizing strain can largely reduce this effect. Itrnis also found that dynamic shear modulus varies linearly with currentrneffective stress on a log-log scale over a wide strain range when therngeneration of excess pore water pressure is considered. An empiricalrnequation is developed to approximately predict the maximum shearrnmodulus when the inclination of major principal stress is considered.