摘要
地震作用下斜坡段桥梁桩基的动力响应特性及损伤程度演化机理尚值得深入研究。文章开展斜坡桩基离心机振动台试验,获得特定坡度条件下各测点的加速度时程曲线;基于桩-坡动力相互作用模型,对比分析桩-坡系统加速度响应特征,验证计算模型和参数取值的合理性;依托某斜坡桩基,通过IDA时程分析,获得斜坡坡度和桩径对桩基动力响应的影响规律,据此建立斜坡桩基地震易损性曲线。研究表明:桩-坡系统存在加速度放大效应,且越靠近坡顶放大效应越明显;桩身最大水平位移和最大正弯矩均位于桩顶处,而最大负弯矩约发生在土-岩交界面处;随地面峰值加速度PGA增大,桩基易损性增大;当PGA相同时,桩基极易由轻微破坏发展为中等破坏,而由严重破坏发展为完全破坏的概率相对较小;桩径越大,桩身弯矩越大,而桩身水平位移及易损性减小;随斜坡坡度增大,桩身弯矩、水平位移及易损性均随之增大。在实际工程设计中,合理布置桩位和设定桩径可有效提高斜坡桩基的抗震性能。
The dynamic response characteristics and damage evolution mechanism of bridge pile foundation in sloping ground under the seismic actions are worth being further investigated.The shaking table tests of centrifuge for pile foundation in sloping ground were carried out,and the acceleration time-history curves for each measuring point given a certain sloping ground were obtained.Based on the dynamic interaction model of pile-sloping ground,the acceleration response characteristics of pile-sloping ground system were compared and analyzed,so the rationality of the calculation model and parameter selection can be verified.Based on the pile foundation in sloping ground,the influential laws of slope angles and pile diameters on the dynamic response of pile foundation were obtained through IDA time-history analysis,and the seismic vulnerability curves of pile foundation in sloping ground were attained.The research results show that the acceleration amplification effect can be observed in the pile-sloping ground system,and the closer to the slope top,the more significant the amplification effect is.The maximum horizontal displacement and the maximum positive bending moment of pile shaft are both located at the pile top,while the maximum negative bending moment of pile shaft occurs at the soil-rock interface.The seismic vulnerability of pile foundation tends to be larger with the increase of ground peak acceleration(PGA).For the same PGA,it is quite easy for the pile foundation to develop from slight damage to moderate damage,but with a comparatively small probability of developing from serious damage to complete damage.With the increase of pile diameter,the bending moment of pile shaft increases,but the horizontal displacement and seismic vulnerability of pile shaft decrease.With the increase of slope angle,the bending moment,horizontal displacement and seismic vulnerability of pile shaft all increase.In practical design,rational pile layout and setting of pile diameter can effectively improve the seismic performance of pile foundation in sloping ground.
作者
尹平保
陆帆
贺炜
万长明
李懿德
张晓曦
Yin Pingbao;Lu Fan;He Wei;Wan Changming;Li Yide;Zhang Xiaoxi(Changsha University of Science and Technology,Changsha 410114,China;Jiangxi Provincial Communications Investment Group Co.,Ltd.,Nanchang 330025,China;Chengdu Surveying Geotechnical Research Institute Co.,Ltd.of MCC,Chengdu 610023,China)
出处
《土木工程学报》
北大核心
2025年第7期66-76,共11页
China Civil Engineering Journal
基金
国家自然科学基金资助项目(52178311,51478051)
湖南省教育厅科学研究项目(20A001)
江西省交通运输厅科技项目(2021H0005)。
关键词
桥梁工程
斜坡桩基
离心机模型试验
IDA时程分析
数值模拟
地震易损性
bridge engineering
pile foundation in sloping ground
centrifuge model test
IDA time-history analysis
numerical simulation
seismic vulnerability
