波浪作用下黄河口粉土孔压响应特征及过程

The Pore Pressure Response Characteristics and Process of the Silt in the Yellow River Delta Under Wave Action

以黄河口海底粉土为研究对象,利用自行研发的监测设备现场监测了波浪作用下海底粉土的孔隙水压力响应过程,获取了2个大风过程中孔隙水压力的有效数据。波浪作用下海底粉土的孔隙水压力响应由表层土最先开始,向下层土延伸,且响应程度随着土层深度的增加而减弱。孔隙水压力响应特征受潮位与波高影响明显,潮位影响孔隙水压力响应的整体趋势而波高影响孔隙水压力响应的幅值,且海底粉土孔隙水压力对波高的响应具有滞后性,滞后时间约为2h。大风过程中海底面以下1.5m以深孔隙水压力未发现明显变化,说明其超过了波浪最大作用深度;海底面以下0.5m位置处孔隙水压力在一段时间内产生剧烈振荡,无明显的累积现象,说明其处于波浪作用范围内,但波浪作用导致的孔隙水压力小于土体孔隙水压力的消散速率。

The pore pressure response processes of the Yellow River delta silt under wave action were monitored by means of the self-developed pore pressure monitoring equipment, and the effective pore pressure data of two gale processes were obtained. Results showed that the pore water pressure response of the silt under wave action begins from the surface of the seabed and then extends downward, and the degree of response decreases with the increase of the depth of the soil layer. The responses of pore water pressure are obviously affected by tidal level and wave height. Tidal level affects the overall trend of pore water pressure response, while wave height affects the amplitude of pore water pressure response. The pore pressure response had lag effect under wave action and the lag time was 2 h. There were no obvious variations of pore water pressure under 1.5 m depth below the seabed during the gale processes, indicating that it beyond the maximum depth of wave action. The pore pressure at the site (0.5 m below the seabed) had a severe oscillation during a period of time without obvious accumulation, which indicating that it was within the range of wave action, but the pore pressure caused by the wave was less than the dissipation rate of the soil.