中文摘要：

对兰州、洛川、杨凌地区黄土在不同含水率与不同应力状态下进行动扭剪三轴试验,测定了黄土的动剪应力-应变关系曲线;同时,依据Hardin-Drnevich双曲线模型,改进了基于动剪应力考虑的土结构性定量化参数,并应用该参数对三地区非饱和黄土的动力结构性进行了分析。结果表明,三地区非饱和黄土的动力结构性参数随动剪应变的增大先降低,而后保持在一个稳定的水平;含水率与固结应力对黄土的动力结构性影响显著,在相同的固结应力条件下,含水率越低,黄土的动力结构性参数越大,在相同的含水率条件下,固结应力越小,黄土的动力结构性参数越大;在相同的条件下,杨凌地区黄土的动力结构性最强,洛川地区黄土次之,兰州地区黄土最弱,即黄土的动力结构性在地理空间分布上存在从西北向东南方向增强的规律。

英文摘要：

The dynamic torsional shear triaxial tests are carried out on loesses of Lanzhou,Luochuan and Yangling under different water contents and different stress states;and then the dynamic shear stress-strain curves of loesses are obtained.Besides,according to Hardin-Drnevich hyperbolic model,the soil structural quantitative parameters,which are based on the dynamic shear stress,are developed;and the dynamic structural characteristics of unsaturated loesses in Lanzhou,Luochuan and Yangling are analyzed by using the parameters.Results show that the structural parameters of Lanzhou,Luochuan and Yangling loesses firstly reduce along with the increase of the dynamic shear strain;and then remain at a stable level;water content and consolidation stress have significant influence on the structural parameters.Under the same consolidation stress condition,the lower water content,the greater dynamic structural parameters of the loess;and under the same water content,the smaller consolidation stress,the greater dynamic structural parameters of the loess.In conclusion,under the same condition,the dynamic structural characteristics of Yangling loess is the strongest;the following is Luochuan loess;and Lanzhou loess is the weakest;in other words,the structural characteristics of loesses in the geographical spatial distribution exists a law of increment from the northwest to the southeast.