【摘要】 波浪作用下海床的稳定性直接影响着海洋构筑物的安全。目前在波土相互作用的研究中,虽然较多地涉及到对海床液化或剪切破坏的分析,但缺乏不同海床计算厚度和饱和度等条件下二者破坏特征的对比研究。本文基于波浪作用下海床应力的解析解,对砂土海床的剪切破坏和瞬态液化破坏特征进行了详细研究和对比。结果分析表明,对于波浪作用下不同饱和度的砂土海床,其剪切破坏深度随海床计算厚度的增加表现为3种变化模式,而其液化深度随海床计算厚度的增加则只表现为1种变化模式。相比非饱和砂土海床,饱和砂土海床计算厚度较小时才可能发生液化,且其液化深度最小,但相同条件下对应的剪切破坏深度却最大。波浪作用下砂土海床存在一个最不稳定厚度,其数值约为(0.2~0.3)倍波长,此时海床最易发生破坏,且破坏深度较大。波浪作用下砂土海床的剪切破坏在波峰和波谷处均可能发生,而瞬态液化只发生在波谷位置,且其液化深度位于剪切破坏深度范围内。更多还原

【Abstract】 Wave-induced seabed instability has an important influence on safety of marine structures.At present,wave-induced seabed liquefaction and shear strength failure have been investigated widely,but there is no further discussion on comparison of the two failure mode with different seabed thickness and saturation.Based on the analytical solution of wave-induced seabed stresses,the characteristics of shear failure and liquefaction of sandy seabed are investigated and compared in detail.The results have shown there are 3kinds of modes for the wave-induced shear failure depth versus seabed thickness,while there is only 1kind of mode for liquefaction depth versus seabed thickness.Compared with unsaturated sandy seabed,the saturated seabed is vulnerable to liquefaction for smaller seabed thickness,resulting in the minimum liquefaction depth and the maximum shear failure depth.There exists an unstable thickness for sandy seabed under wave loadings,which is about(0.2-0.3)times of the wavelength.For the unstable thickness,the seabed is vulnerable to failure and the failure depth is relatively large.Wave-induced shear failure of sandy seabed is likely to occur in the wave crest and wave trough zone,but the transient liquefaction only occurs in wave trough zone,and the liquefaction depth is smaller than the corresponding shear failure depth.更多还原