考虑负摩阻力作用的超长桩荷载传递计算

Load transfer calculation of super-long piles considering negative friction

基于超长桩试验资料,采用考虑负摩阻力作用的广义双曲线荷载传递模型反映桩侧土弹塑性、软化与稳定三阶段工作特性,桩端采用双曲线荷载传递模型模拟土体的非线性变形特性,并且引入Mindlin解以考虑桩侧摩阻力在桩端处产生的桩端位移,从而建立了层状软土地基中超长桩荷载传递分析理论。该理论可用于计算多层地基中超长桩的桩侧阻力、沉降以及极限承载力,也可用于分析层状地基中超长桩的荷载传递规律。通过工程实例计算与实测对比分析,可知计算得到的荷载-沉降曲线与实测的曲线较为吻合,因此该理论可作为确定桩承载力的依据。该理论可靠、方法简单,且具有较好的适用性。

Based on the test data of super-long pile,the general hyperbolic load transfer model taking account of negative friction was used to reflect the performance characteristics of the pile side soil in nonlinear,softening and stabilization stages.The hyperbolic load transfer model was used for the pile end to simulate the nonlinear deformation properties of soil.The Mindlin＇s solution was adopted to calculate the pile end displacement at lateral friction resistance.The analytical theory of load transfer for super-long piles in stratified soft soil foundation was established,which could be used not only to calculate lateral friction resistance,settlement and bearing capacity of super-long piles in stratified foundation,but also to analyze the load transfer law of super-long piles.Comparison of calculated results and measured data shows the derived load-settlement curve is closely agree with testing results.The theory can be used for determining the bearing capacity of super-long piles,and it is theoretically reliable,simple in application and useful in practice.