| 地震作用下特大型桥梁嵌岩桩基础动力响应 |
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| 引用本文： | 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.地震作用下特大型桥梁嵌岩桩基础动力响应[J].交通运输工程学报,2018,18(4):53-62. |
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| 作者姓名： | 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 |
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| 作者单位： | 1.海南省交通运输厅, 海南 海口 5702162.长安大学公路学院, 陕西 西安 7100643.中国公路工程咨询集团有限公司, 北京 1000894.陇东学院土木工程学院, 甘肃 庆阳 7450005.广东省交通规划设计研究院股份有限公司, 广东 广州 5105076.中咨华科交通建设技术有限公司, 北京 1001957.滁州学院地理信息与旅游学院, 安徽 滁州 239000 |
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| 基金项目： | 国家自然科学基金项目41272285海南省交通科技项目HNZXY2015-045R |
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| 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。
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| 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 |
| 收稿时间： | 2018-04-04 |
Dynamic response of rock-socketed pile foundation for extra-large bridge under earthquake action |
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| 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.Dynamic response of rock-socketed pile foundation for extra-large bridge under earthquake action[J].Journal of Traffic and Transportation Engineering,2018,18(4):53-62. |
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| Authors: | 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 |
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| Abstract: | 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 intensity, and the pile foundation is damaged. Cracks easily occur at near the junction of pile top and cap, the soft-hard soil interface and bedrock surface under seismic action, and the seismic design of the bridge pile foundation should be considered. |
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