The silty seabed in the Yellow River Delta (YRD) is exposed to deposition, liquefaction, and reconsolidation repeatedly, during which seepage flows are crucial to the seabed strength. In extreme cases, seepage flows could cause seepage failure (SF) in the seabed, endangering the offshore structures. A critical condition exists for the occurrence of SF, i.e., the critical hydraulic gradient ($i_{\mathrm{cr}}$). Compared with cohesionless sands, the $i_{\mathrm{cr}}$ of cohesive sediments is more complex, and no universal evaluation theory is available yet. The present work first improved a self-designed annular flume to avoid SF along the sidewall, then simulated the SF process of the seabed with different consolidation times in order to explore the $i_{\mathrm{cr}}$ of newly deposited silty seabed in the YRD. It is found that the theoretical formula for $i_{\mathrm{cr}}$ of cohesionless soil grossly underestimated the $i_{\mathrm{cr}}$ of cohesive soil. The $i_{\mathrm{cr}}$ range of silty seabed in the YRD was 8–16, which was significantly affected by the cohesion and was inversely proportional to the seabed fluidization degree. SF could “pump” the sediments vertically from the interior of the seabed with a contribution to sediment resuspension of up to 93.2–96.8%. The higher the consolidation degree, the smaller the contribution will be.

中文翻译：

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固结时间对黄河三角洲新沉积粉质海床临界水力梯度的影响

黄河三角洲（YRD）的粉质海底反复遭受沉积，液化和固结作用，在此期间，渗流对海底强度至关重要。在极端情况下，渗流可能会导致海床的渗流破坏（SF），危及近海结构。存在SF的临界条件，即临界水力梯度（${\mathrm{一世}}_{铬}$）。与无粘性砂相比，${\mathrm{一世}}_{铬}$粘性沉积物的分类更为复杂，尚无通用的评价理论。本工作首先改进了一种自行设计的环形水槽，以避免沿侧壁出现SF，然后模拟了具有不同固结时间的海床的SF过程，以探索海床的SF。${\mathrm{一世}}_{铬}$三角洲新沉积的粉质海底的数量。发现理论公式为${\mathrm{一世}}_{铬}$ 无粘性土壤被严重低估了 ${\mathrm{一世}}_{铬}$粘性土壤。这${\mathrm{一世}}_{铬}$长江三角洲粉质海床的范围为8–16，这受内聚力的影响很大，与海床的流化度成反比。SF可以从海床内部垂直“抽出”沉积物，对沉积物的重悬贡献高达93.2–96.8％。合并程度越高，贡献将越小。