波浪荷载下海床稳定性的总应力法分析

Total stress approach for stability of seabed under wave loads

评价海床稳定性是海工建筑物设计所考虑的重要部分。基于经典弹性理论,采用半逆解法,推导了线性波浪荷载下成层弹性海床的总应力解答,在此基础上根据莫尔库仑破坏准则进行了海床剪切破坏分析,分析表明:随海床深度线性增加的土体剪切模量对应力角分布具有明显影响,特别是当海床厚度小于半倍波长时,最容易发生破坏的位置位于海床表面以下一定深度,而对于均质海床,最容易发生破坏的位置位于海床表面。软弱夹层对海床的稳定性存在影响,埋深越浅的软弱夹层越容易导致其上部土层的剪切破坏。

The evaluation of seabed stability is an important part for the design of various marine facilities. Based on the classic theory of elasticity, the total stress solutions for layered elastic seabed under linear wave loads are derived by means of the semi-inverse method, and then according to the Mohr-Coulomb failure criterion, seabed shear failure is analyzed on the basis of the solutions. The results show that the shear modulus of soils which increases linearly along with the seabed depth has a significant effect on the distribution of stress angle, especially when the seabed thickness is less than a half times the wavelength. The easiest place to initiate shear failure is located at a certain depth below the seabed surface. However, for the homogeneous seabed, it is located at the surface of seabed . The stability of seabed is also affected by weak interlayer. The more shallow the depth of the weak interlayer, the more easily the shear failure of soil layer occurs on the weak interlayer.