摘要
基于海南铺前大桥,采用室内模型试验与数值仿真,分析了断层-桩-岩土相互作用时桥梁桩基的距离效应与承载特性。研究结果表明:在模型试验中,对于直径为6.3 cm,长度为60 cm的桩基,当断层与桩基水平距离由9.45 cm增加到22.05 cm时,承载力增幅为26.7%,当水平距离由22.05 cm增加到31.50 cm时,承载力增幅仅为3.8%,断层与桩基水平距离对桩基承载力影响度降至6.5%,可以忽略;当桩长一定,荷载相同时,断层与桩基水平距离越小,桩身轴力变化越小;当断层与桩基水平距离由9.45 cm增加到22.05 cm时,桩身30 cm处桩侧阻力增大了0.059 kN,水平距离对桩侧阻力影响度降低了44.5%,当水平距离由22.05 cm增加到31.50 cm时,桩侧阻力增大了0.029 kN,水平距离对桩侧阻力影响度降低了8.3%。在数值仿真中,在桩基直径为1.5 m,长度为30 m,覆盖层厚度为10 m的工况下,当断层与桩基水平距离由1.5 m增加到6.0 m时,承载力增幅由11.0%减小到6.5%,当水平距离由6.0 m增加到7.5 m时,承载力增幅减小到4.9%;当断层与桩基水平距离由7.5 m减小到1.5 m时,桩身轴力沿桩长方向减小趋势逐渐变缓,当桩长一定,荷载相同时,断层与桩基水平距离越小,桩身轴力变化越小;当断层与桩基水平距离由1.5 m增加到6.0 m时,桩身16 m处桩侧阻力增大了1.90 MN,水平距离对桩侧阻力影响度降低了28.0%,当水平距离由6.0 m增加到7.5 m时,桩侧阻力增大了0.33 MN,水平距离对桩侧阻力影响度降低了5.0%。模型试验与数值仿真结果均表明,在5倍桩径范围内,桩基竖向承载特性受断层与桩基水平距离的影响较大;超出5倍桩径后,水平距离的影响较小,甚至可以忽略;断层与桩基水平距离对承载力、桩侧阻力的影响度与桩侧阻力占比的仿真值均减小较快,在水平距离为5倍桩径时,较模型试验值分别降低了2.2%、6.0%、0.174,结果较理想化,可用作工程参考。
Based on the Hainan Puqian Bridge,the distance effect and bearing characteristics of bridge pile foundation under the fault-pile-rock interaction were analyzed by the indoor model test and numerical simulation.Research result shows that,in the model test,for a pile foundation with a diameter of 6.3 cm and a length of 60 cm,when the horizontal distance between the fault and the pile foundation increases from 9.45 cm to 22.05 cm,the bearing capacity of pile foundation increases by 26.7%.When the horizontal distance increases from 22.05 cm to 31.50 cm,the bearing capacity increases by only 3.8%,and the influence degree of the horizontal distance on the vertical bearing capacity reduces to 6.5%and may be neglected.When the length of pile foundation is constant and the load is the same,the smaller the horizontal distance,the smaller the change of axial force of pile foundation.The horizontal distance increases from 9.45 cm to 22.05 cm,the side resistance of pile foundation increases by 0.059 kN at the 30 cm of pile foundation length,and the influence degree decreases by 44.5%.When the horizontal distance increases from 22.05 cm to 31.50 cm,the side resistance increases by 0.029 kN,and the influence degree decreases by 8.3%.In the numerical simulation,under the condition that the diameter,length and overburden thickness of pile foundation are 1.5,30,and 10 m,respectively,when the horizontal distance increases from 1.5 m to 6.0 m,the increment of the bearing capacity reduces from 11.0%to 6.5%.When the horizontal distance increases from 6.0 m to 7.5 m,the increment reduces to 4.9%.When the horizontal distance reduces from 7.5 m to 1.5 m,the axial force of pile foundation decreases gradually along the length direction of pile foundation.When the length of pile foundation is constant and the load is the same,the smaller the horizontal distance,the smaller the change of axial force of pile foundation.When the horizontal distance increases from 1.5 m to 6.0 m,the side resistance of pile foundation at the 16 m of pile foundat
作者
冯忠居
陈慧芸
袁枫斌
尹洪桦
李孝雄
刘闯
张福强
王蒙蒙
李少杰
FENG Zhong-ju;CHEN Hui-yun;YUAN Feng-bin;YIN Hong-hua;LI Xiao-xiong;LIU Chuang;ZHANG Fu-qiang;WANG Meng-meng;Li Shao-jie(School of Highway,Chang'an University,Xi'an 710064,Shaanxi,China;China Highway Engineering Consultants Corporation,Beijing 100089,China;Jinan Highway Administration Bureau,Jinan 250014,Shandong,China;School of Geographic Information and Tourism,Chuzhou University,Chuzhou 239000,Anhui,China;Department of Transport of Hainan Province,Haikou 570204,Hainan,China)
出处
《交通运输工程学报》
EI
CSCD
北大核心
2019年第2期36-48,共13页
Journal of Traffic and Transportation Engineering
基金
国家自然科学基金项目(51708040)
海南省交通科技项目(HNZXY2015-045R)
关键词
桥梁工程
桩基
断层
室内模型试验
数值仿真
竖向承载力
轴力
侧阻力
影响度
bridge engineering
pile foundation
fault
indoor model test
numerical simulation
vertical bearing capacity
axial force
side resistance
influence degree
