Field measurement of the erosion threshold of silty seabed in the intertidal flat of the Yellow River Delta with a newly-developed annular flume

Frontiers in Marine Science

Marine Science

Zhenhao Wang¹  Shaotong Zhang²  Yonggang Jia³  Liang Xue³  Hanlu Liu³  Yongzheng Quan³  Hongxian Shan³  Zhenghui Li³  Zhiwen Sun³  Tian Chen³  Zhuangcai Tian⁴ 

[1] First Institute of Oceanography, Ministry of Natural Resources (MNR), Qingdao, Shandong, China;Key Laboratory for Submarine Geosciences and Prospecting Techniques (Ministry of Education), College of Marine Geosciences Ocean University of China, Qingdao, China;Shandong Provincial Key Laboratory of Marine Environment and Geological Engineering, College of Environmental Science and Engineering, Ocean University of China, Qingdao, China;State Key Laboratory for Geomechanics and Deep Underground Engineering, China University of Mining and Technology, Xuzhou, China;

关键词: in-situ;    erosion experiment;    bed shear stress;    critical shear stress;    Yellow River delta;   

DOI  :  10.3389/fmars.2023.1177241

 received in 2023-03-01, accepted in 2023-05-17,  发布年份 2023

来源: Frontiers

【 摘 要 】

Accurately measuring the critical shear stress is crucial for numerous applications, such as sediment transport modeling, erosion prediction, and the design of sustainable coastal engineering structures. However, developing reliable and precise in-situ measurement devices faces significant challenges due to the harsh and dynamic nature of aquatic environments. Factors like turbulence and waves introduce complexities that must be considered when designing and calibrating these devices. The newly developed Openable Underwater Carousel In-situ Flume (OUC-IF) was used to determine the critical shear stress (τc) and quantify erosion rates. Acoustic Doppler Velocimeter (ADV) was employed to measure 3D near-bottom velocities, which were then used to estimate and pre-calibrate bed shear stress (τ) applied on the seabed in the annular flume. Three computation methods of shear stress were evaluated: turbulent kinetic energy (TKE), direct covariance (COV), and log profile (LP). In-situ erosion experiments were conducted for the first time at two sites in the tidal flat of the Yellow River Delta (site 1 with a water depth of 1.32 m and site 2 with a water depth of 0.75 m). The critical shear stress was found to be 0.10 Pa at site 1 and 0.19 Pa at site 2, and the erosion rates of the sediments were successfully measured. The effect of wave-seabed interactions on erosion resistance was explored by theoretically estimating the wave-induced pore pressure of the seabed based on the observed data. The max liquefaction degree of the seabed at site 1 and site 2 was 0.035 and 0.057, respectively, and the average erosion coefficient Me was 2.63E-05 kg m-2s-1 at site 1 and 3.48E-05 kg m-2s-1 at site 2.

【 授权许可】

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Copyright © 2023 Liu, Jia, Zhang, Shan, Xue, Sun, Quan, Li, Chen, Tian and Wang