黄河三角洲沉积物含盐量与其临界剪切应力的关系研究

Relationship Between Salt Content of Undisturbed Sediment and Its Critical Shear Stress

黄河入海径流量变化引起河口区盐度场的改变,从而影响沉积物的动力学行为和工程性质。在黄河三角洲4个不同沉积年代的叶瓣采集柱状样,采用统计和相关性分析的方法对不同深度原状沉积物的含盐量、临界剪切应力以及其他物理力学性质进行分析。结果表明:黄河三角洲不同沉积年代、不同深度沉积物含盐量变化范围是0.2‰~2.0‰,整体剖面定义为"均匀型";在研究区范围内,沉积物临界剪切应力呈现空间不均匀分布,并随沉积物含盐量的增大而增大。表层沉积物临界剪切应力偏小,高容重、低含水率的沉积物偏大。研究对于黄河口冲淤研究具有重要意义。

The salinity field in the Yellow River estuary is influenced by the discharge from the Yellow River to sea,which influences the dynamic behavior and engineering properties of the sediment. Sediment cores were collected at four Yellow River delta lobes with different deposition periods. The salt content,critical shear stress and other physical and mechanical properties of the undisturbed sediments at different depths are studied by statistics and correlation analysis method. Experimental results showed that： the sediment salt content range between 0. 2‰ and 2. 0‰ at different depths of the selected lobes. Overall,depth profiles can be defined as＂uniform type＂; in the study area,the critical shear stress of sediments is characterized by an asymmetric spatial distribution in this study area,and increases as the sediment salt content gets larger. Critical shear stress of surface sediments is relatively small,while sediments with higher volume weight and lower water content have a relatively large value of critical shear stress. This research has great significance for the studies of erosion and deposition in estuaries.