摘要
针对2021年青海玛多7.4级地震中野马滩大桥的桥台震害,开展基于Pushover分析的桥台纵桥向破坏机理研究。提出土-桩-桥台精细化有限元模拟方法,以及基于地勘资料的模型土体参数确定实用方法,建模方法和加载模式要点为:(1)适用于土-桥台相互作用的分布式p-y弹簧修正模型;(2)可识别背墙弯曲、剪切或弯-剪多种破坏模式的背墙非线性梁柱单元-墙底非线性剪切单元串联模型;(3)土-搭板和土-翼墙摩擦弹簧;(4)基于分布式间隙单元的可捕捉地震中主梁与背墙接触位置变化的Pushover加载模式,从而实现了桥台纵桥向地震损伤破坏全过程模拟。结果表明:野马滩桥台在水平地震作用下,背墙底截面先发生屈服,随后背墙剪力达到抗剪能力峰值,桥台整体水平承载力开始退化,直至背墙底完全剪断,而桩基础并不发生明显损伤。总体而言,桥台破坏模式为背墙弯-剪破坏,数值分析结果与桥台实际震害相符。
In order to investigate the longitudinal failure mechanism of abutment of Yematan Bridge against the 2021 Ms7.4 Maduo Earthquake,a Pushover numerical analysis is carried out.To this end,a refined finite element method of simulating soil-pile-abutment system is proposed,and a practical method of determining soil parameters is developed based on geotechnical reports with limited data.The modeling method and the loading scheme have the following features:(1)modified distributed p-y spring model applicable to soilabutment interaction,(2)a series model of a backwall nonlinear beam-column element and a bottom nonlinear shear spring,which is capable of identifying multiple backwall failure mechanisms,including flexural failure,shear failure,and flexure-shear failure of backwall,(3)friction springs for soil-slab and soil-wingwall,and(4)distributed gap element-based Pushover loading mode which can capture the varied girder-backwall contact location during earthquakes.Accordingly,the longitudinal seismic failure process of the bridge abutment can be effectively simulated.The Pushover analysis results reveal that under the horizontal ground loading,the backwall of the Yematan bridge firstly yields at its bottom section.After that,the shear force of backwall reaches the peak shear capacity and the overall horizontal shear capacity of bridge abutment reduces until the complete failure of backwall bottom,while pile foundation does not suffer obvious damages.Generally,the bridge abutment fails in the flexural-shear failure mode,and the numerical analysis results agree well with actual earthquake damage to the bridge abutment.
作者
周成
叶爱君
王晓伟
庞于涛
包绍伦
Zhou Cheng;Ye Aijun;Wang Xiaowei;Pang Yutao;Bao Shaolun(State Key Laboratory of Disaster Reductionin Civil Engineering,Tongji University,Shanghai 200092,China;China University of Geosciences(Wuhan),Wuhan 430074,China;CCCC First Highway Consultants Co.,Ltd.,Xi'an 710068,China)
出处
《土木工程学报》
EI
CSCD
北大核心
2024年第5期53-64,共12页
China Civil Engineering Journal
基金
国家自然科学基金(52178155,52008155)
中央高校基本科研业务费专项资金(02002150169)。
