【摘要】 黄河水下三角洲分布着大量的扰动粉土层,其微观结构与未扰动粉土相比有显著差异。基于浅地层剖面探测、钻探取样等技术,利用电子扫描显微镜、图像处理等方法来研究扰动粉土的微观结构特征。结果表明,扰动粉土与未扰动粉土两者在结构类型、颗粒之间的接触方式、粒度组成、定量参数等方面均存在显著差异。扰动粉土与非扰动粉土的结构类型都属于骨架状结构,不同的是扰动粉土以直接接触为主,粒间无细粒及黏粒成分相隔。扰动粉土粒度组成偏向粗化,孔隙比降低、含水率升高、饱和度升高、比重增大、颗粒圆形度降低、颗粒分形维数降低。同时探讨了扰动粉土微观结构差异原因及其与工程地质性质之间的关系,认为在波浪作用下粉土中孔隙水的渗流带走细粒物质,颗粒发生重新排列从而导致微观结构变化,进而使其强度得以提高。更多还原

【Abstract】 Disturbed silt is widely distributed in the subaqueous delta of the Yellow River,contrasting with undisturbed silt it is different in microstructure.Based on the technologies of sub-bottom profiler Probe,Drilling Sampling and SEM and Image Process,we studied the microstructural characteristics of the disturbed silt.It turns out that compared with the undisturbed silt there are lots of differences in microstructure,grain composition,quantitative parameters.Two silt are skeletal structure,but disturbed silt particles focus on direct contact and separated from each other by the same particles.Compare with the undisturbed silt,disturbed silt have coaser particles,lower void ratio,higher moisture content,higher saturation,higher specific gravity,lower circularity and higher fractal dimension.At the same time,we discussed the formation mechanism,microstructural difference and the engineering geological properties of disturbed silt.The wave action is the main factor for the formation of disturbed silt,and under the influence of it,the pore water seepages taking fine particles out and the particles re-arrange,which leads to the change of micro structure and engineering geological properties of silt.更多还原