干湿循环环境下超长桩荷载传递特性研究

Super Long Pile Load Transfer Mechanism Nnder Environment of Dry-wet Circle

为掌握干湿循环环境下的超长桩的工作机理及桩侧摩阻力、桩端阻力的软化规律。通过对湖区典型淤泥质粘土的室内干湿循环模拟试验,得到了土体强度随干湿循环作用次数的呈乘幂函数形式的衰减规律。基于荷载传递解析法,提出了基于广义干湿循环下超长桩荷载传递理论模型。选取某湖区高速公路实际工程的实测数据与计算结构分析与对比验证,验证表明桩侧摩阻力和桩端阻力衰减模型可以很好地解决桩周土体在干湿循环条件下的引起桩基承载力衰减和桩顶沉降增大的计算难题。为南方湿热地区、湖泊等富水地区等典型干湿循环环境下的的高速公路桩基设计施工、安全评价及预警具有重要的工程实际意义。

To masterworking mechanismof super long pileunder dry-wet cycleand thepile side friction resistance and pile tip resistancesoftening law,based on the super long pile project of the typical silt clay foundation in the lake district,the load transfer characteristics of the super long piles under dry-wet cycle are studied.Through the simulation test ofindoor dry-wet cycling of typical silt clay in the lake area,getting the attenuation law ofsoil strength in the form of the power function with wet and dry cycle times.Based onthe Analysismethod of load transfer,loadtransfer theory modelof super long pileunder dry-wet circleis be put forward.Selecting experimental data and computational structural analysis and contrast-verification of alake area expresswayactualproject,verification showed that the attenuation model of thepile side friction resistance and pile tip resistancecan be better to solve thedifficulty in calculation ofattenuation of pile foundation bearing capacity and increase of pile top settlement caused by thepile of soilunder the condition of dry-wet cycles.It has important practical significance for the design and construction, safety assessment and early warning of the highway pile foundation of typical wet and dry cycle environment,such as wet and humid regions,lakes and other water rich regions and so on.