中文摘要：

通过对萧山正常固结饱和软黏土进行应力控制的循环三轴试验，着重研究了初始偏应力对动弹模量（土动剪模量）及阻尼比的影响。试验结果表明，在相同的动应变水平下，随着初始偏应力的增加，土体动模量Ed、Ekmax以及Ed/Edmax与阻尼比D都有较大幅度的增加。在试验的基础上，通过指数函数建立了反映动模量Ed、Edmax以及Ed/Edmax与动应变之间关系的经验公式。同时，采用指数函数建立了阻尼比D与Ed/Edmax关系表达式来间接模拟初始偏应力作用下阻尼比的变化规律。与以往的二次函数曲线相比，得到了更为精确的结果。

英文摘要：

The dynamic elastic modulus and damping ratio of normally consolidated soft clay subjected to undrained cyclic triaxial loading are investigated at different initial deviator stresses. It＇s observed that the effect of initial deviator stress on dynamic soil behavior is very significant. With increase of the initial deviator stress, the dynamic elastic modulus Ed, fdmax, normalized modulus fd/fdmax and material damping ratio D increase greatly. Predictive equations for estimating dynamic elastic modulus Ed, Edmax, normalized modulus Ed/Edmax and damping ratio D are presented. The equations are based on an exponential function. The equations for damping ratio are expressed in terms of normalized modulus Ed/Edmax. Comparisons between the predictive equations developed and the earlier previously published curves show exponential function can better model dynamic damping ratio than quadratic function.