Consolidation of sediments discharged from the Yellow River: implications for sediment erodibility

Abstract

Consolidation processes acting on an intertidal mudflat in the Yellow River delta, China, were investigated using field and laboratory experiments. The dissipation of excess pore pressure was examined in an excavated experimental plot to characterise the short-term consolidation of sediments discharged from the Yellow River. Changes in sediment strength were monitored over a 5-year period, together with measurements of physical and mechanical properties using laboratory experiments. In addition, the erodibility of silty sediments under wave loading conditions was also tested in the field. Results showed that sediments discharged from the Yellow River experienced a high rate of consolidation after initial deposition. Excess pore pressure dissipated completely after approximately 45 to 51 h. Sediments were then in a state of quasi-overconsolidation and showed heterogeneity in strength. Hydrodynamic action appears to be crucial to sediment consolidation in the primary period and plays a decisive role in the development of a stiff stratum. Changes in sediment strength due to wave-induced secondary modifications over varying temporal and spatial scales are consistent with variations in sediment erodibility. This factor should be considered in the development of erosion models for intertidal mudflat sediments.