黄河下游冲积粉土地震液化判别研究

在粉土或砂土分布广泛的地区，地震液化是导致地基失稳和上部结构受损的直接原因之一，深入分析研究土体地震液化机理对建筑抗震减灾有着极其重要的意义。黄河下游地理位置特殊，该区域内粉土分布面积广大，具有一定的代表性。本文基于大量的实际调查，系统地分析了黄河下游冲积粉土的成因及土体组成，并在动三轴试验基础上阐述了该区域粉土的动力特性和液化机理，最后结合该区域粉土土质特点和工程实例比较了现有的地震液化判别方法，指出该区域粉土液化判别应考虑粘性粉粒的影响，并依此利用塑性指数对液化判据进行了改进。

Study on assessment of earthquake liquefaction of alluvial silt in lower reaches of Yellow River

In the area where the saturated sand or silt distributes wide, the soil liquefaction caused by earthquake is one of the direct masons for the invalidation of the foundation and the collapse of structures. Therefore, it is necessary to research carefully the mechanism of soil liquefaction in order to avoid great destruction caused by earthquake. Tne special geographic location of the lower reaches of Yellow River makes it a typical area where silt distributes wide. Based on abundant practical investigations , the formation and the composition of the silt are analyzed detailedly in this paper, and the dynamic properties and liquefaction mechanism of silt are also illuminated on the basis of dynamic triaxial test. Finally, combined with the properties of silt and several engineering examples, a comparison was presented between liquefaction assessment methods being used. Furthermore, it is indicated that the influence of cohesive silt should be taken into account in the liquefaction assessment, and that could be realized with the plasticity index.