波浪作用下黄河三角洲粉质土海床动力响应分析

应用饱和土动力固结理论和Pastor-Zienkiewicz III动力本构关系，对波浪作用下黄河三角洲粉质土海床的动力响应特征进行了有限元分析，应用总超孔压准则对海床进行了液化判别，并将计算结果与现场观测资料进行对比。结果表明：波浪导致的海床超孔压由瞬态孔压和累积孔压两部分组成；相比均质海床，拥有表面硬层的海床瞬态孔压沿深度衰减更快，累积孔压在表层增长速度更大；不同波浪条件下，瞬态孔压值及其变化趋势较为一致，累积孔压则具有较大的不同。年平均波浪条件下海床不会发生液化；5 a和50 a一遇极端波浪条件下，考虑三维效应和具有表面硬层的海床更容易液化，最大液化深度在海床表面以下2～3 m范围内。计算所得的海床最大液化深度与实测的黄河三角洲海底灾害地貌深度有较好的一致性，表明了文中方法的有效性和合理性。

Analysis of wave-induced dynamic response of silty seabed in Yellow River delta

Based on the dynamic consolidation theory of saturated soil and the dynamic constitutive model Pastor-Zienkiewicz III, the wave-induced dynamic response of the silty seabed in the Yellow River delta is examined. Liquefaction potential is estimated using a total excess pore pressure criterion. The liquefaction depth calculated is compared with the site observed data at last. Results indicate that the wave-induced excess pore pressure contains two parts: the transient and the residual one. A quicker reduction with depth of the transient pore pressure and a more significant accumulation of the residual pore pressure in the surface layer tend to happen in the seabed that with a surface hard layer rather than a homogeneity one. Under different wave conditions, the value and the variation trend of the transient pore pressure are similar, while distinct differences are found in the residual pore pressure. Under the annual mean wave condition, liquefaction is impossible to happen. While liquefaction would occur under the 5 and 50 years once wave conditions, a greater liquefaction possibility and a bigger liquefaction depth tend to occur while the three-dimensional effect and a surface hard layer of the seabed are considered, the biggest liquefaction depth is within 2-3 meters under the seabed surface. The calculated liquefaction depth is in good agreement with the depth of the submarine disastrous landforms in the Yellow River delta. It is indicated that the method is effective and reasonable.