新疆伊犁黄土的物性指标、动力学特性与滑坡

Physical index,dynamic property and landslide of Ili loess

分析了伊犁谷地28个黄土样品的粒径、密度、含水量和孔隙比，测试了震陷、湿陷、动弹模量和塑性指数，探讨了伊犁谷地黄土的物性、动力学特征，讨论了它们与滑坡之间的关系。伊犁谷地的原生黄土主要以粉粒为主，含量为74％，大于75μm的颗粒含量为10％，小于5μm的颗粒含量为15％；黄土天然含水量为4％～16．1％，谷地东部的黄土明显地比谷地西部的更细，伊犁黄土的孔隙比在0.832～0．907之间，有相当的湿陷性。在含水量低于20％时，还会有湿陷。黄土的塑性指数为9左右，比较小，粘粒含量低，易损性大，抗震性能差，具有较强的震陷性。在同样的动应变下，伊犁黄土的动模量较小，随着动应变的增大，其动模量衰减较快。冻融季节是伊犁地区滑坡的多发季节，构造活动强烈的地段也是地质灾害的多发地段。

We analyzed the particle size, density, water content and void ratio of 28 loess samples in the Ili valley and tested the seismic subsidence, collapsibility, dynamic modulus and plasticity index. The physical property and dynamic characteristic of loess in the Ili Valley were discussed. The relationship between the loess characteristic and the landslide was talked over. The primary loess of Ili valley was formed in late Pleistocene and is mainly composed of silt particle, including 74 percent. The particle of 75 -5μm is 10 percent and that less than 5 μm is 15 percent; the natural water content of loess is 4 -16.1 percent. The loess of the east valley is obviously finer than that of the west valley. It indicates that the loess was rooted in the west hungriness and related to the conveying function of the westerly wind. The void ratio of Ili loess is 0. 832 - 0. 907, going with considerable collapsibility. Although the water content is less than 20 percent, the collapse may happen. The plastic index of the loess is about 9, comparatively small. The clay content is low and the vulnerability is high. The seismic performance is bad and the seismic subsidence is comparatively strong. Under the same dynamic strain condition, the dynamic modulus of Ill loess is smaller. With the accretion of dynamic strain, the attenuation of dynamic modulus is quick. The landslide often happens in the spring melting season, caused by freezing-thawing function in winter. The geological disaster also happens in the distinctly active structure. It is great valuable for reference to recognize the characteristic of Ili loess and prevent the loess landslide.