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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。
Loess has obvious regional distribution in our country. It is of practical significance to grasp the distribution law of dynamic characteristic parameters from space plane. Under the condition of different water content and different stress, undisturbed loess in Lanzhou, Luochuan and Yangling was taken as the research object. The triaxial tests of the dynamic loosening and shearing were carried out. The dynamic shear modulus and damping ratio of the loess were measured. The results show that the dynamic shear modulus of intact loess in Lanzhou, Luochuan and Yangling gradually decreases with the increase of dynamic shear strain, and the decreasing range is getting smaller and smaller. , The dynamic shear modulus of intact loess in Yangling area is significantly affected by the initial dynamic shear modulus. Under the same water content and consolidation stress, the initial dynamic shear modulus of undisturbed loess in Lanzhou, Luochuan and Yangling is in the geographical space The distribution of the loess is the smallest, the loess is the second in the Luochuan area, and the loess in the Yangling area is the largest, increasing from northwest to southeast. The damping ratio of intact loess in Lanzhou, Luochuan and Yangling generally follows The increase of shear strain shows an upward trend. There is also a regional difference in damping ratio of undisturbed loess with dynamic shear strain in three areas. Loess in Lanzhou is the largest, loess in Luochuan is the second, and loess in Yangling is the smallest Northwest to southeast direction to reduce.