中文摘要：

基于指数函数的有界性、函数曲线形状和构造土体动力本构模型的一般原则，把函数Y=e^x在（-∞，0]区间上的图像进行翻转、平移、放缩，从而构造出土体的动力本构模型的骨架曲线。在卸载和反向加载时，采用与骨架曲线相同的函数形式，并以前一次卸载开始点作为起点，以土体的极限应力水平作为渐近线，构造出土体动力本构模型的滞回曲线。在此基础上构造出适用于非对称循环荷载的指数形式土体动力本构模型（UE模型）。并用共振柱实验的结果检验了模型的有效性。UE模型具有四个特点：第一，适用于非对称循环荷载；第二，记忆量小；第三，卸载再加载滞回曲线自动满足Masing准则；第四，模型参数少，物理意义明确，可用常规试验确定。

英文摘要：

Based on the boundedness and the form of exponential function, and also based on the general rules for constructing soil dynamic constitutive model, the function image of y = e^x in interval （ - ∞ , 0 ] is overturned and translated and also magnified or reduced so as to gain the skeleton curve of soil dynamic constitutive model. In terms of unloading and loading on opposite side , let the stress-strain curve have the same form of skeleton curve. The curve uses the last unloading point as its starting point, and uses soil＇s ultimate stress level as its asymptote, and then the hysteretic curve is constructed. Thus soil dynamic constitutive model having exponential form is gained, which is suitable for unsymmetrical cyclic loadings. The model is also called UE model, and the resultS of resonance column test indicate UE model is effective. UE model has such traits as flowings： firstly, UE model is suitable for unsymmetrical cyclic loadings;secnondly, UE model needs only a few memories;thirdly, UE model＇ s hysteretic curves under unloading-reloading following Masing＇ s rule automatically;fourthly, UE model has only a few parameters, and these parameters have clear physical meaning, which could be determined by conventional tests.