In-situ experimental study on pore-water pressure response and consolidation mechanism of the surface sediments in tidal flat of Yellow River delta under tide and wave loading

In order to study the pore pressure response and consolidation mechanism of the surface sediments in the tidal flat of the Yellow River delta under the action of wave and tide loading. At the tide flat of the Yellow River estuary, The fluid sediments imitating the rapidly deposited seabed silty soils were made in situ, and the fluid sediments were promptly filled into a one-meter deep pit excavated at the tide flat. By the static cone penetration test and the pore water piezometer test, a comparative study was conducted about the pore-water pressure response of pit soils and the tidal flat soils under the action of waves and tides loading, meanwhile the non-uniform consolidation mechanism of the tidal flat soils was discussed. It was shown that the pore-water pressure response between the the tidal flat soils and the pit soils were different under the tide loading, in the process of rising and falling tide, the excess pore-water pressure of the pit soils underwent negative-zero-positive changes, it was equivalent to a process of loading and unloading, however the tidal flat soils only produced negative excess pore-water pressure. Under the coupling action of tide and wave loading, the accumulation of pore water pressure was obvious in the surface soils of tidal flat, the maximum excess pore water pressure was generated near a depth of 0.3 meters. The strength of the tidal flat soils in the Yellow River delta presents the phenomenon of high-low-subhigh non-uniform consolidation along the depth, the mechanism of this phenomenon is related to the characteristics of pore pressure response of tidal flat soils under the tide loading and coupling action of tide and wave loading, especially near the surface of 0.3 meters of soils, which is significantly affected by long-term wave loading and formed a hard shell layer.