波浪和海底底床的相互作用（2）--床底应力及位移分布

系统分析了波浪作用下海底底床中的应力及位移分布,考虑了不同加载波参数、弹性模量、饱和度及底床厚度对底床应力分布的影响,并计算了不同砂质的土骨架水平位移和垂向位移,比较了饱和底床和非饱和底床,这些结果可应用于海洋结构物的设计

Simulation of a buried pipeline crossing strike-slip fault based on Vector Form Intrinsic Finite Element (VFIFE) method with fiber element model

The buried pipeline subjected to strike-slip fault would experience large deformation and cause tensile rupture or shear failure of the pipe wall. In order to investigate the mechanism of potential failure position (PFP) of a pipeline, a numerical approach based on the Vector Form Intrinsic Finite Element (VFIFE) method with fiber beam element model (VFIFE-fiber model) is developed. Several key factors, such as geometrical nonlinearity, material nonlinearity, and the interaction between axial force and bending moment are considered. A simple and practicable formula for obtaining the PFP of a pipeline is proposed. © Copyright 2016 by the International Society of Offshore and Polar Engineers (ISOPE)

A New Model for Sediment Transport

The problem of predicting sediment transportation by water waves is treated analytically with the rate of wave energy dissipation or wave damping. With resorting to the theory of shallow water waves and the basis of Yamamoto’s Coulomb-damped poroelastic model, the Boussinesq-type equation has been derived over a variation depth bed. For convenience Cnoidal wave is just discussed, The Cnoidal wave with complex wave length and wave velocity, which are as a function of wave frequency, water depth, permeability, Poisson’s ratio and complex elastic moduli of bed soil, is applied to analyse the rate of sediment transportation. Considering the sediment transportation depended on the shear stress near-bed or the horizontal velocity, the conclusion of Yamamoto’s experiment in clay bed has been extended to general situation. It could be figured out that the model should provide a method to avoid the undistinguishable factors during sediment transport processes and relate mass transport with the sediment peculiarities

预测沙波运移的谱分析模型

沙波运移预测是海洋开发必不可少的一环。通常采用非线性谱分析方法分析沙波实测资料从而预测沙波运移。然而这种方法仅是从统计的角度进行预测,它不包含水动力、加载风速、沙质底床性质等关键因素对沙波运移的影响。对此本文提出了一种谱分析模型解决此类问题。该模型基于沙波形状不变假设,引入波谱能量平均运移速度,考虑了台风产生的风浪和涌浪,利用波浪输沙理论计算台风期间的沙波运移,厘清了一般波流作用和台风作用引起的沙波位移。模型计算结果与实测数据吻合,可以用来预测10~20年内的沙波活动和底床演化

波浪作用下粉土特性分析

利用弱非弹性介质模型,推导了波浪作用下有限深海床内部孔隙水压力、应力以及土骨架和孔隙水位移关系。针对3种海洋土,分析了土床内孔隙水压力、应力、应力角、位移的分布以及弹性波随加载波周期的变化。结合前人的实验结果,讨论了在粉土质海床中所呈现的共振现象。从理论上探讨了该现象发生的力学机制,提出了土床中硬土层的存在是决定土床中是否可能发生共振的必要条件,并且可以预测共振发生的可能区域

波浪作用下海底底床的运动

探知海底底床运动既是实际工程中遇到的一个比较普遍的问题，也是海洋沉积学理论研究中经常涉及到的。比如，在海底管线的铺设时，在考虑海上石油平台的具体位置时，在研究海底地貌变迁沙波沙脊走向等等问题。预报波浪引起的海床运动特别在是极端波况下有着非常重要的意义。本文从理论上探讨底床的运动，得到一个简单易行数学公式，为工程实际应用提供参考依据

比较两种模型下饱和土的动态响应

比较Biot和Yamamoto两种模型下饱和土的动态响应，指出了这两种土模型的特点．首先从土骨架和孔隙水所满足的运动方程出发分析了两种土模型所反映能量损耗，然后计算了粗砂质和细砂质土层内弹性波随加载频率及土参数的衰减规律，总结了黏性摩擦和Coulomb摩擦在两种模型中具体体现，最后讨论了当加载为海浪时，两种模型对应的波浪衰减特点以及土床内孔隙水压力和应力相位角随孔隙度、渗透系数、黏性系数及剪切模量等土参数的变化