现代黄河三角洲沉积物临界剪切应力研究  

Field measurement of sediment critical shear stress in the modern Yellow River Delta

作　　者：郑杰文[1,2] 贾永刚[2] 刘晓磊[2] 刘保华 付腾飞[1] 张丽萍[2] 

机构地区：[1]国家海洋局第一海洋研究所海洋沉积与环境地质国家海洋局重点实验室,山东青岛266061 [2]中国海洋大学海洋环境与生态教育部重点实验室,山东青岛266003 [3]国家深海基地管理中心,山东青岛266061

出　　处：《海洋学报》2015年第3期86-98,共13页

基　　金：国家自然科学基金项目(41272316;41402253);中国博士后基金项目(2014M561963);山东省博士后创新基金项目(BSH2014001)

摘　　要：为研究现代黄河三角洲沉积物临界剪切应力空间分布特征及其影响要素,本文在现代黄河三角洲不同沉积区域,垂直海岸线布设测线,采用黏结力仪进行沉积物临界剪切应力测试,并在相应测点开展沉积物物理力学性质与粒度成分测量工作。研究结果表明高潮滩沉积物临界剪切应力最高,在1.1~4.02Pa之间,沉积物不易发生侵蚀,含水量低、干容重大、黏粒与粉粒含量高、平均粒径小、不排水剪切强度大是高潮滩沉积物临界剪切应力偏高的重要因素;中潮滩沉积物受生物活动影响显著,临界剪切应力在0.10~1.90Pa之间,生物活动扰动、生物排泄及遗体遗迹的程度与数量是造成不同区域测试差异的重要原因;低潮滩沉积物临界剪切应力很低,在0.08~0.80Pa之间,沉积物极易发生侵蚀,含水量高、干容重偏低、砂砾含量高、平均粒径大、不排水剪切强度小是其典型的沉积物物理力学性质,也是造成低潮滩沉积物临界剪切应力普遍低于高潮滩的重要原因;现代黄河三角洲沉积物临界剪切应力区域特征表现为北部沉积物临界剪切应力水平最低,在0.11~0.4Pa之间,东部最高,在2.8~4.55Pa之间,南部与东北部居中,分别在0.63~0.84Pa与0.83~2.99Pa之间,东北部空间非均匀性分布显著,粒度组分的分异是导致沉积物临界剪切应力区域差异显著的重要因素,黏粒含量高的沉积区域沉积物临界剪切应力普遍高于砂砾含量高的沉积区;与世界其他大型河口三角洲相比,现代黄河三角洲沉积物临界剪切应力水平偏低但非均匀程度较高。Cohesive sediment meter was used to measure sediment critical shear stress along the measuring line perpendicular to coastal line in different sedimentary lobes in the modern Yellow River delta.These obtained sediment critical shear stress,combined with the test results of sediment physical and mechanical properties and granularity composition,then were used to study on the distribution of sediment erodibility in the modern Yellow River Delta and its relationship with the influencing factors.This study indicated that,（1）high tidal flat was hard to be eroded with high critical shear stress ranging from 1.1to 4.02 Pa,which was due to the following factors including the low water content,high dry bulk density,high content of silt and clay particles,small average particle diameter,and high undrained shear strength;（2）middle tidal flat was characterized with obviously different critical shear stress ranging from 0.10 to 1.90 Pa,which was mainly influenced by biological activities in different sedimentary lobes including biodisturbation,biological waste,remains and remnants with different amounts and degree;and（3）low tidal flat can be easily eroded with low critical shear stress ranging from 0.08 to 0.80 Pa,which was induced by the high water content,low dry bulk density,high sand content,gentle average particle diameter,and low undrained shear strength.For the whole modern Yellow River Delta,low,middle and high the critical shear stress occur in the northern part,middle part and the southern part of the delta,respectively.The discrepancy of particle compositions can be considered as the critical factor for causing the variety of sediment critical shear stress in different areas.Compared with other main estuarine deltas in the world,non-uniform degree of sediment erodibility was higher and anti-erosion strength was lower in the modern Yellow River Delta.

关 键 词：临界剪切应力 沉积物 黏结力仪 河口三角洲 侵蚀 

分 类 号：P343.5[天文地球—水文科学]