中文摘要：

为揭示黄河口水下三角洲硬壳层的土性特征和风浪作用下的液化破坏状况，选择典型研究区，在现场利用普氏贯入仪测试硬壳层的强度特征，原位取1m原状样进行室内土工试验；利用重锤锤击荷载板的方式模拟波浪对硬壳层的动力作用，通过孔压探头和普氏贯入仪实时监测土体内孔压和振动前后强度的变化；通过理论计算研究硬壳层在不同风浪等级下的液化深度。通过研究发现，（1）硬壳层土体基本上处于超固结状态，且超固结比随深度增加而减小，大王北和刁口地区硬壳层强度约是新滩和广利港的两倍，离河口近的地区强度的变异系数比远的地区要大；（2）根据孔压随振次的变化关系，现场土体在振动过程中，孔压的增长经历了4个阶段，即初始阶段、增长阶段、稳定阶段和衰减阶段，且表层土体达到液化，深层的未液化；（3）大王北硬壳层在6-10级风浪下的平均液化深度仅为7-11cm，新滩和广利港硬壳层在6-10级风浪作用下的液化深度达32-42cm。强度高的硬壳层液化深度小，低的液化深度大，这种液化深度的差异性造成了地貌上的凹凸不平。

英文摘要：

This paper examines the soil characteristic and liquefaction degree of hard shell seams at the subaqueous delta of the Yellow River. Four typical areas were chosen for measuring, testing and studying. The hard shell seam strength was measured by in - situ Proctor penetrometer. Undisturbed soil sample of 1 m long was excavated for laboratory soil property test. Sledge hammers were dropped down freely to hit the load board to simulate the wave force acted on the hard shell seam. The excess pore pressure and strength variation were observed. The liquefaction depth of the hard shell seams at four study areas under different wave storms were calculated by theory. From the studies, some conclusions were gotten： （1）the hard shell seams are in overconsolidated state, and overconsolidation ratio decreases with depth. The strength of the hard shell seams at Dawangbei and Diaokou are twice of those at Xintan and Guangli ports. The strength variation coefficient near the estuary is bigger than those far from estuary. （2） According to the pore pressure variation with vibration times, the pore pressure variation can be divided into four stages, initial stage, growth stage, stabilization stage and attenuation stage. During vibration, the surface soil liquefied, however the deeper soil did not liquefy. （ 3 ） The liquefaction depth of the hard shell seam at Da Wang Bei is 7 to 11 cm under 6th to 10th storms, and they reach 32 to 42cm at Xin Tan and Guang Li ports. The lique-faction depth of the hard shell seam with high strength was small, however the seam with low strength liquefied deeper, thus the difference of liquefaction depth caused the non - uniformity of seabed.