短峰波作用下饱和海床中的单桩响应分析

Analysis of a Single Pile Response in a Saturated Seabed Under Short-Crested Wave

采用准静态三维数值分析方法直接模拟短峰波作用于海床表面与桩身的三维波压力分布,在考虑了海床土体的流固耦合和桩土界面的接触特征的基础上,研究了短峰波荷载作用下饱和砂质海床中的单桩响应问题.根据数值分析结果,研究了波浪荷载作用下土体的孔压变化规律、桩柱的位移和弯矩分布情况,探讨了桩土接触面不同处理方式的影响,并与自由海床和完全埋置单桩的模型结果进行比较.结果表明:泥线附近与桩端处土体的响应局部现象明显;采用桩土耦合模型时,孔压与弯矩响应相比于接触面模型有放大效应,而位移响应则正好相反.完全埋置桩在波浪作用下的响应主要受海床影响,在桩柱伸出海面的模型中,波浪荷载在桩柱上的影响起主导作用.

A 3D FEM model of a single pile in saturated sandy seabed was proposed to study the reponse of pile.Meanwhile,the quasi-static method and fluid-soil coupling and contact behavior on interface was considered.Based on numerical results,responses of the pore water pressure and stress of seabed soil under wave was studied,and the deformation and internal force of the single pile were discussed.Besides,two different methods to model the pile-soil interface were discussed with a comparison of the free field seabed model and seabed model with a totally embeded pile.The results show that the pore water pressure increases significantly near the mudline and bottom of pile.Responses of pore pressure and bending moment are evidently larger in the coupling model,but the displacement response is smaller.Moreover,the totally embeded pile model is mainly affected by seabed,as the wave dominatedly acts on the model with a pile out of the seabed.