【摘要】 黄土在我国具有明显的区域分布特征,从空间平面上把握其动力特性参数的分布规律具有一定的现实意义。以不同含水率与不同应力状态下兰州、洛川、杨凌地区原状黄土为研究对象,进行动扭剪三轴试验,测定了黄土的动剪切模量与阻尼比的变化规律。结果表明,兰州、洛川、杨凌地区原状黄土的动剪切模量随动剪应变的增加而逐渐减小,且减小的幅度越来越小;含水率与固结应力对兰州、洛川、杨凌地区原状黄土的动剪切模量与初始动剪切模量影响显著;在相同含水率和固结应力下,兰州、洛川、杨凌地区原状黄土的初始动剪切模量在地理空间分布上具有一定的规律性,兰州地区黄土最小,洛川地区黄土次之,杨凌地区黄土最大,即从西北向东南方向增大;兰州、洛川、杨凌地区原状黄土的阻尼比总体上随动剪应变的增大呈现上升趋势,且三个地区原状黄土的阻尼比随动剪应变的增长速率也存在区域性差异,兰州地区黄土最大,洛川地区黄土次之,杨凌地区黄土最小,即从西北向东南方向减小。更多还原

【Abstract】 In China,loess has obvious regional distribution characteristics,and there is a certain practical significance to grasp the distribution laws of its dynamic characteristic parameters from the space plane.The dynamic torsional shear triaxial tests are carried out on undisturbed loess of Lanzhou,Luochuan and Yangling under different moisture contents and different stress states,and the variation laws of dynamic shear modulus and damping ratio of loess are obtained.The results show that the dynamic shear modulus of Lanzhou,Luochuan and Yangling loess decrease gradually with the increase of dynamic shear strain,and the decrease rate becomes smaller and smaller.The moisture content and consolidation stress have significant influences on the dynamic shear modulus and the initial dynamic shear modulus.Under the same moisture content and consolidation stress,the initial dynamic shear modulus of Lanzhou,Luochuan and Yangling loess conform to the law of increment from the northwest to the southeast in the geographical spatial distribution,the dynamic shear modulus of Lanzhou loess is the smallest,the following is that of Luochuan loess,and that of Yangling loess is the largest.As a whole,the damping ratios of Lanzhou,Luochuan and Yangling loess increase with the increase of dynamic shear strain.The increase rate of the damping ratios in the three regions conform to the law of decrement from the northwest to the southeast,the damping ratio of Lanzhou loess is the largest,the following is that of Luochuan loess,and that of Yangling loess is the smallest.更多还原