摘要
地震作用下,水-结构耦合效应使结构浸水部分产生动水压力。为了研究动水效应对不同形式桥墩的地震响应影响和动水压力在桥墩上的分布规律。以某大型圆形桥墩、矩形桥墩及高桩承台群桩基础为例,采用基于势流体的有限单元法,建立流固耦合数值计算模型,进行了不同水深工况下及不同地震波输入下的自振特性分析、地震响应分析及动水压力分析。结果表明:水深的增加会使3种形式桥墩的自振频率降低,内力响应增大;矩形桥墩在地震输入方向上的迎水面为平面,相比圆形桥墩与水的相互作用更明显,会产生更大的动水压力;当达到一定水深时,圆形桥墩和矩形桥墩上的动水压力沿墩高先增大后减小。且迎水面中心位置处动水压力最大,向两侧逐渐减小;水下高桩承台群桩基础的中桩所受的地震响应及动水压力均比边桩小。水深淹没承台后,承台承受大部分动水压力,桩基上动水总压力作用点在0.6倍的桩长位置处。
Under action of earthquake,water-structure interaction effect makes submerged part of structure produce hydrodynamic pressure.Here,to study effects of hydrodynamic effect on seismic responses of different forms of piers,and distribution laws of hydrodynamic pressure on piers,taking a large round pier,a rectangular pier and a pile group foundation with high pile cap as examples,fluid-solid coupling numerical calculation models for 3 examples were established by using the finite element method based on potential fluid,and their natural vibration characteristics analyses,seismic response analyses and hydrodynamic pressure analyses under different water depth conditions and different seismic wave inputs were performed.The results showed that increase in water depth can reduce natural vibration frequencies and increase internal force responses of 3 pier-forms;upstream surface of rectangular pier in direction of earthquake input is plane,interaction between rectangular pier and water is more obvious than that between circular pier and water,and this interaction can produce larger hydrodynamic pressure;when a certain water depth is reached,hydrodynamic pressure on circular and rectangular piers firstly increases and then decreases along pier height;hydrodynamic pressure at center position of upstream surface is the largest and gradually decreases to both sides;seismic response and hydrodynamic pressure of middle pile of pile group foundation with underwater high pile cap are smaller than those of side piles;after water depth submerges pile cap,pile cap bears most of hydrodynamic pressure,and action point of total hydrodynamic pressure on pile foundation is at position of 0.6 pile length.
作者
周敉
江坤
李久龙
ZHOU Mi;JIANG Kun;LI Jiulong(Key Laboratory for Old Bridge Detection and Reinforcement Technology of the Ministry of Transportation,Chang’an University,Xi’an 710064,China;Zhejiang Jiaogong Advanced-grade Highway Maintenance Co.,Ltd.,Hangzhou 310051,China;China Design Group Co.,Ltd.,Nanjing 210014,China)
出处
《振动与冲击》
EI
CSCD
北大核心
2022年第21期7-18,共12页
Journal of Vibration and Shock
基金
国家自然科学基金(51978062)
山西省交通科技项目(2021-02-03)
陕西省创新人才推进计划-科技创新团队(2018TD-040)
长安大学中央高校基本科研业务费专项资金(300102212209)
陕西省自然科学基础研究计划项目-联合基金(2021JLM-47)。
关键词
深水桥墩
势流体单元
流固耦合
自振特性
地震响应
动水压力
deep-water pier
potential fluid element
fluid-solid coupling
natural vibration characteristics
seismic response
hydrodynamic pressure
