FIELD TESTING OF THE ERODIBILITY OF TIDAL FLAT SEDIMENT IN THE MODERN YELLOW RIVER DELTA

The erodibility of a tidal flat is important to shoreline stability, and concerns the strategic decision for coast protection. In July of 2008, in-situ measurement of erodibility for surficial sediment were conducted using a self-developed recirculating seawater flume on the tidal flat of the modern Yellow River delta. Selected physical-mechanical sediment properties were measured at the same time.Results show that the critical erosion shear stress of the surficial tidal sediments varies between 0.088 Pa and 0.254 Pa. The nonuniform erodibility of surficial tidal sediments causes pitting. The factors influencing critical erosion shear stress of sediment are complicated. Among all the factors,the shear strength is closely related to critical erosion shear stress and there is a good linear relation between the two. The difference between the measured values of critical erosion flow velocity and the calculated values using different formulas is remarkable. In this regard, the more objective critical erosion condition can only be obtained through in-situ measurement.