基坑开挖对管桩竖向承载性状影响研究  

Research on the Influence of Foundation Pit Excavation on the Vertical Bearing Characteristics of Pipe Piles

作　　者：杨庆光[1] 肖森 刘峰[1] 柳雄 YANG Qingguang;XIAO Sen;LIU Feng;LIU Xiong(College of Civil Engineering,Hunan University of Technology,Zhuzhou Hunan 412007,China)

机构地区：[1]湖南工业大学土木工程学院,湖南株洲412007

出　　处：《湖南工业大学学报》2025年第1期19-25,78,共8页Journal of Hunan University of Technology

基　　金：湖南省自然科学基金资助项目(2024JJ7152);湖南省教育厅科学研究基金资助项目(23A0424);湖南省大学生创新创业训练计划基金资助项目(湘教通[2024]118号3705)。

摘　　要：针对基坑开挖引起管桩挤土效应的弱化,以及挤土效应弱化对管桩承载性质影响问题,开展了室内模型试验,并通过对模型试验进行数值建模,验证了数值模型的可靠性。在此基础上,从桩长、桩间距、桩侧摩阻力系数对开挖卸荷影响下管桩基础承载性状的影响展开研究。结果表明:开挖卸荷对管桩承载特性造成较大影响,极限承载力对应桩顶沉降量提高54.5%;数值计算发现,卸载前后极限荷载所对应最大沉降差率为9.52%,满足工程精度要求,验证了所提数值模型的可靠性;数值计算结果表明,随桩长提高,最大桩身轴力位置不断上升,而中性点位置却不断下降;桩间距越小,开挖卸荷对桩身轴力影响越大,而对负摩阻力影响越小;摩阻力系数为0.3时,摩阻力系数对桩身轴力及桩侧摩阻力发挥敏感度最高。In view of the weakening of the soil squeezing effect caused by the foundation pit excavation and the influence of the this weakening on bearing characteristics of the pipe piles,indoor model experiments have been conducted,with the reliability of the numerical model verified through numerical modeling of the model experiment,followed by a study on the influence of pile length,pile spacing,and pile lateral friction coefficient on the bearing characteristics of pile foundations under excavation unloading on the former basis.The results show that excavation unloading has a significant influence on the bearing characteristics of pipe piles,with the ultimate bearing capacity corresponding to a 54.5%increase in pile top settlement.Numerical calculations have found that the maximum settlement difference rate is 9.52%corresponding to the ultimate load before and after unloading,which meets the engineering accuracy requirements,thus verifying the reliability of the proposed numerical model.The numerical calculation results show that as the pile length increases,the maximum axial force position of the pile body keeps rising,while the neutral point position continues to decline.The smaller the distance between piles,the greater the influence of excavation and unloading on the axial force of the pile body,and the smaller the influence on negative frictional resistance.With the friction coefficient being 0.3,the sensitivity of the friction coefficient to the axial force of the pile body and the lateral friction of the pile reaches the highest point.

关 键 词：承载性状 挤土效应 侧摩阻力 管桩 基坑开挖 

分 类 号：TU753[建筑科学—建筑技术科学]