黄河口侵蚀再悬浮物海床内部输供及控制因素研究

The primary goal of the project is to reveal sediments,eroded and resuspended massively in Yellow River estuary, not only come from the seabed surface stirred up by waves, but also partly from underpart of seabed through seepage,to quantify the contribution of the sediment moving up from underpart in the process of sediment erosion and resuspension, and to construct the forcasting model for sediment "pump" transport.The research is composed of four sub-tasks which are (1)research on the relationship between "pump" process and accumulation of pore water pressure in sediment; (2)research on the governing factors of "pump" process, occurrence criterion, and the computational method of sediment pumpage; (3)research on the numerical description of the contribution of sediment pumpage in the process of sediment erosion and resuspension; (4) research on the post rework of sediment "pump" process continuely on the seabed sediments.In the implementation plan, an in-situ observation station is chosen to conduct the long-term automatic observation on the dynamic processes of the benthic boundary layer and the hydrodynamic conditions; Cone Penetration Test(CPT) and sediment sample collection is carried out periodically to proceed laboratory analysis; physical simulating experiments are developed in the field tidal flat and laboratory; and numerical simulation and calculation is finally proceeded basing on the "pump" process.The achivements being obtained in this research can promot the further understanding of the modern sedimentary dynamic process, and provide guidance on the prediction and control work on the geological hazards in the subaqueous Yellow River delta.

本项目旨在揭示黄河口海区发生大规模侵蚀再悬浮的沉积物，不仅来自于目前已被认识的波浪"掀起"的海床表面沉积物，还有部分可能来自于海床内部沉积物向海床表面的渗流输运"泵送"，评估海床内部向上"泵送"输运的沉积物量对侵蚀再悬浮量的贡献，建立波浪作用下黄河口海床内部沉积物"泵送"输运过程定量描述方法。研究内容包括：（1）"泵送"过程，与波浪作用及沉积物孔隙水压力累积与液化的对应关系；（2）"泵送"控制因素，发生判据，发生量的定量预测方法；（3）"泵送"对侵蚀再悬浮物贡献的定量描述；（4）持续向上"泵送"作用对海床沉积物的改造作用。研究方法采用现场设立原位观测点，长期观测海底边界层动态变化过程及海洋动力状况；在黄河口潮坪和实验室，开展物理模拟试验，观测"泵送"过程；基于观测结果对"泵送"发生过程进行数值模拟分析。研究成果可深入认识黄河口沉积物侵蚀再悬浮动力机制，并可为黄河水下三角洲侵蚀灾害防治提供。

本项目首先揭示了黄河口海区发生大规模侵蚀再悬浮的沉积物，不仅来自于目前中已被认识的波浪“掀起”的海床表面沉积物，还有部分来自于海床内部沉积物向海床表面的渗流输运“泵送”。其次，通过室内外物理模拟实验与现场原位长期观测的方法，定量评估了海床内部向上“泵送”输运的沉积物量对侵蚀再悬浮量的贡献， 建立波浪作用下黄河口海床内部沉积物“泵送”输运过程定量描述方法。研究成果可深入认识黄河口沉积物侵蚀再悬浮动力机制，并可为黄河水下三角洲侵蚀灾害防治提供支持。