加筋路堤下刚性桩复合地基变形特性分析  

Deformation Characteristics of Rigid Pile Composite Foundation with Reinforced Embankment

作　　者：陈仕文 唐昌意 李栋 CHEN Shi-wen;TANG Chang-yi;LI Dong(Zhuhai Institute of Urban Planning&Design,Zhuhai,Guangdong 519000,China)

机构地区：[1]珠海市规划设计研究院,广东珠海519000

出　　处：《公路交通科技》2024年第8期106-113,共8页Journal of Highway and Transportation Research and Development

基　　金：住房和城乡建设部科技示范项目(2021-S-058);广东省住房和城乡建设厅科技创新计划项目(2021-K4-021299,2020-K4-534762);珠海市产学研合作项目(ZH22017001200149PWC)。

摘　　要：刚性桩复合地基在珠海地区软土区道路工程中应用时常出现沉降和不均匀沉降较大的问题,进而引发沿路管线破坏和路面波浪起伏。为了解决深厚软土区刚性桩复合地基存在的沉降和差异沉降过大问题,优化复合地基设计,为防治道路病害提供参考,本研究通过数值计算方法建立了平面应变模型。将三维桩体和桩帽进行二维等效,并考虑了路堤填注和土体固结的过程,分析了基准工况和不同参数条件下加筋路堤下刚性桩复合地基变形特性。结果表明:刚性桩复合地基的变形可分为变形协调区、统一沉降区和压缩变形区,其中变形协调区主要影响差异沉降,压缩变形区主要影响总沉降,统一沉降区则因自身压缩变形小,随复合地基整体下沉,而起到减小总沉降的作用;在桩两端约束强于桩中部约束的情况下,边桩可能首先在中部发生弯曲破坏;刚性桩复合地基施工过程中出现的路堤外隆起现象会在工后逐步消失并在路堤带动下发生沉降;参数分析结果表明,持力层的强度、桩端嵌入持力层深度对路堤沉降影响最大,而桩间距、桩帽尺寸对差异沉降影响最大,场坪土的强度及砂黏性、褥垫层厚度、地下水深度对路堤沉降均有一定影响,但影响较为有限。因此,对于深厚软土区域,根据软土厚度确定桩长并合理增大桩间距和桩帽尺寸,可以控制路堤沉降并节省工程造价。The application of rigid pile composite foundation often encounters the problems of large and uneven settlement in soft soil area of Zhuhai.That leads to the damage of pipelines along road and undulation of road surface.To solve the problems of excessive settlement and differential settlement in rigid pile composite foundation in deep soft soil areas,to optimize the design of composite foundation,and to provide the reference for prevention and control of road diseases,a plane strain model is established by using numerical method.The 3D pile body and pile cap are equivalent to 2D,and the processes of embankment filling and soil consolidation are considered.The deformation characteristics of rigid pile composite foundation with reinforced embankment under the benchmark conditions and different parameters are analyzed.The result indicates that the deformation of rigid pile composite foundation can be divided into deformation coordination area,unified settlement area,and compression deformation area.The deformation coordination area mainly affects the differential settlement.The compression deformation area mainly affects the total settlement.The unified settlement zone plays a role in reducing total settlement as the composite foundation sinks as a whole due to its small compression deformation.When the restraint at both ends of pile is stronger than that in the middle of pile,the bending failure of side pile may occur in the middle first.The uplift phenomenon outside embankment during the construction of rigid pile composite foundation will gradually disappear after construction,and the settlement will occur under the drive of embankment.The parameter analysis result shows that the strength of bearing layer and depth of pile end embedded in the bearing layer have the greatest impact on embankment settlement,while the pile spacing and pile cap size have the greatest influence on differential settlement.The strength and sand viscosity of earthwork,the thickness of cushion,and the depth of groundwater all have certain

关 键 词：道路工程 变形特性 数值计算 刚性桩复合地基 软基处理 

分 类 号：U41[交通运输工程—道路与铁道工程]