ABSTRACT

The present study investigates the influence of nonlinear waves on the oscillatory pore pressure-induced response around buried pipes. The study is carried out considering the applicable wave theories namely: linear, Stokes, cnoidal and solitary wave theories. The soil modelling is based on Biot’s consolidation equations which are solved using Finite Element tool COMSOL Multiphysics. Two case studies are considered for the investigation where the parameters of wave height and water depth are varied respectively for each case study to increase the wave nonlinearity. The hydrodynamic pressure on the seabed is based on the applicable wave theory which is chosen from Le-Mehaute’s diagram. The pore pressures, stresses and forces developed on the buried pipe are evaluated considering different wave theories. As the wave transforms from linear to cnoidal through stokes waves a gradual variation in the wave-induced soil response is observed, whereas the soil response from cnoidal to solitary waves is found to be considerably abrupt. It is observed that the magnitude of these wave-induced forces and stresses due to a solitary wave can be about twice that of a linear wave under a wave crest. Similarly, for the case of pipe under wave trough, linear wave theory gives a very high estimate of uplift force as compared to highly nonlinear solitary waves.

摘要

本研究调查了非线性波对埋管周围的振荡孔隙压力引起的响应的影响。该研究是在考虑适用的波浪理论的基础上进行的，即：线性、斯托克斯、连续波和孤立波理论。土壤建模基于使用有限元工具 COMSOL Multiphysics 求解的 Biot 固结方程。研究考虑了两个案例研究，其中每个案例研究的波高和水深参数分别变化，以增加波浪的非线性。海床上的水动力压力基于从 Le-Mehaute 图表中选择的适用波浪理论。考虑不同的波浪理论，对埋管上产生的孔隙压力、应力和力进行评估。随着波通过斯托克斯波从线性波转变为cnoidal，观察到波浪引起的土壤响应的逐渐变化，而从cnoidal到孤立波的土壤响应被发现相当突然。据观察，由孤立波引起的这些波浪引起的力和应力的大小可能是波峰下线性波的两倍。类似地，对于波谷下的管道，与高度非线性的孤立波相比，线性波理论给出了非常高的上浮力估计值。据观察，由孤立波引起的这些波浪引起的力和应力的大小可能是波峰下线性波的两倍。类似地，对于波谷下的管道，与高度非线性的孤立波相比，线性波理论给出了非常高的上浮力估计值。据观察，由孤立波引起的这些波浪引起的力和应力的大小可能是波峰下线性波的两倍。类似地，对于波谷下的管道，与高度非线性的孤立波相比，线性波理论给出了非常高的上浮力估计值。