为得到跨海桥梁桩基础在波流荷载下的动力响应特征,以新建湄洲湾港口铁路支线综合标段罗屿特大桥为研究对象,运用有限元计算手段,建立了圆形桩-波浪-海床耦合模型,研究了线性波和椭圆余弦波作用下桩基础的位移、应力及位移频域响应.结果表明:线性波作用下,桩基础的位移和应力均呈规律性的周期变化,桩顶位置的位移响应峰值约海床面处的4.2 倍,海床面位置的应力响应峰值约桩顶位置处的1.6 倍,桩顶位移的主频集中在0.11 Hz,接近桩基础的固有频率;椭圆余弦波作用下,桩基础的位移呈随机变化规律,应力呈规律性的周期变化,桩顶位置的位移响应峰值约海床面处的5.5 倍,海床面位置的应力响应峰值约桩顶位置处的1.7 倍,桩顶位移的一阶主频为0.16 Hz,二阶主频为0.38 Hz.
Research on Strong Wave Dynamic Response Characteristics of Beam Pile Foundations of Large Cross Sea Bridges
In order to obtain the dynamic response characteristics of the beam pile foundation of a cross sea bridge under wave and current loads,the Luoyu Extra Large Bridge in the comprehensive section of the newly built Meizhou Bay Port Railway Branch Line was taken as the research object.Using finite element calculation methods,a circular pile-wave-seabed coupling model was established to study the displacement,stress,and displacement frequency domain response of the pile foundation under the action of linear waves and cnoidal waves.The results show that under the action of linear waves,the displacement and stress of the pile foundation exhibit regular periodic changes.The peak displacement response at the pile top is about 4.2 times that at the seabed,and the peak stress response at the seabed is about 1.6 times that at the pile top.The main frequency of the pile top displacement is concentrated at 0.11 Hz,which is close to the natural frequency of the pile foundation.Under the action of cnoidal waves,the displacement of the pile foundation shows a random variation pattern,and the stress shows a regular periodic variation.The peak displacement response at the top of the pile is about 5.5 times that at the seabed,and the peak stress response at the seabed is about 1.7 times that at the top of the pile.The first-order main frequency of the displacement at the top of the pile is 0.16 Hz,and the second-order main frequency is 0.38 Hz.
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