摘要
依托铺前大桥实体工程,基于人工质量模型和桩-土惯性相互作用机理,通过振动台模型试验,选用叠层剪切式模型箱,模拟了自由场在地震作用下的振动反应,分析了0.15g^0.60g(g为重力加速度)地震动强度下大直径桥梁嵌岩桩基础加速度、相对位移、弯矩等响应特性和损伤情况等。研究结果表明:桩基础加速度峰值从桩底至桩顶呈增大趋势,加速度放大系数随地震动强度的增大逐渐减小,输入地震波为0.55g时,桩顶加速度放大系数趋于稳定值1.34;桩顶加速度时程响应频率低于桩底加速度时程响应频率,上部覆盖层对地震波的放大作用和滤波效应明显;随着地震动强度的增大,桩顶相对位移峰值近似呈线性增大,在0.15g^0.60g地震动强度下,桩顶相对位移峰值变化范围为1.97~6.73mm;桩基础弯矩沿桩长呈"3"字形变化,上部软硬土层分界处和基岩面附近弯矩达到峰值,并随地震动强度的增大而增大,地震动强度为0.50g时达190.9kN·m,超过桩身抗弯承载力;桩基础基频随地震动强度的增大呈整体降低趋势,在0.50g地震动强度下,其基频较0.35g地震动强度下低50.1%,桩基础产生损伤;桩顶与承台连接处、上部覆盖软硬土层界面和基岩面附近桩身在地震作用下易产生裂缝,桥梁桩基础抗震设计时应着重考虑。
Combined with the Puqian Bridge project and based on the interaction mechanism of artificial mass model and pile-soil inertia,the vibration response of free field under seismic actionwas simulated by the vibration table model test and the laminated shear model box.The response characteristics of acceleration,relative displacement and bending moment,as well as the damage of large diameter bridge rock-socketed piles under the ground vibration intensity of 0.15 g-0.60 g（gis gravity acceleration）were analyzed.Research result shows that the acceleration peak value of pile foundation increases from the pile bottom to the pile top.The acceleration amplification coefficient decreases with the increase of ground vibration intensity.When the ground vibration intensity is 0.55 g,the acceleration amplification coefficient of pile top tends to a stable value of1.34.The acceleration time-history response frequency of pile top is lower than that of pile bottom.The upper cover layer has obvious effect on seismic wave amplification and filtering effect.With the increase of the ground vibration intensity,the relative displacement peak value of pile top approximately increases linearly.Under the ground vibration intensity of 0.15 g-0.60 g,the peak value variation range of relative displacement of pile top is 1.97-6.73 mm.The bending moment of pile foundation changes in a＂3＂shape along the length of the pile,and it reaches the peak value at the upper boundary between soft and hard soil layer and near the bedrock surface.The peak value of bending moment increases with the ground vibration intensity.When the ground vibration intensity is 0.50 g,the peak value of bending moment reaches 190.9 kN·m.The bending moment exceeds the bending capacity of the pile.With the increase of ground vibration intensity,the fundamental frequency of pile foundation decreases as a whole.Under the ground vibration intensity of 0.50 g,the frequency of pile foundation decreases by 50.1%,compring with that under the action of 0.35 gground vibration i
作者
刘闯
冯忠居
张福强
吴敬武
董芸秀
尹洪桦
袁枫斌
李孝雄
文军强
LIU Chuang;FENG Zhong-ju;ZHANG Fu-qiang;WU Jing-wu;DONG Yun-xiu;YIN Hong-hua;YUAN Feng-bin;LI Xiao-xiong;WEN Jun-qiang(Department of Transport of Hainan Province,Haikou 570216,Hainan,China;School of Highway,Chang＇an University,Xi＇an 710064,Shaanxi,China;China Highway Engineering Consultants Corporation,Beijing 100089,China;School of Civil Engineering,Longdong University,Qingyang 745000,Gansu,China;Guangdong ProvinceCommunications Planning and Design Institute Co.,Ltd.,Guangzhou 510507,Guangdong,China;Zhong Zi Hua Ke Traffic Construction Technology Co.,Ltd.,Beijing 100195,China;School ofGeographic Information and Tourism,Chuzhou University,Chuzhou 239000,Anhui,China)
出处
《交通运输工程学报》
EI
CSCD
北大核心
2018年第4期53-62,共10页
Journal of Traffic and Transportation Engineering
基金
国家自然科学基金项目(41272285)
海南省交通科技项目(HNZXY2015-045R)
关键词
岩土工程
强震区
嵌岩桩基础
动力特性
振动台模型试验
geotechnical engineering
meizoseismal area
rock-socketed pile foundation
dynamic characteristic
shaking table model test
