大直径负摩擦灌注长桩荷载-沉降关系研究

提出大直径灌注长桩工作性状并同时考虑负摩阻力的桩侧荷载传递模型，桩端采用双曲线荷载传递模型模拟土的非线性变形特性，并引入混凝土的Rusch模型来考虑高荷载水平作用下桩身混凝土的弹塑性性状，采用Mindlin解答以考虑桩侧摩阻力在桩端处产生的桩端位移，从而建立了层状地基中大直径负摩擦灌注长桩的荷载传递分析理论。根据该理论计算得到的荷载一沉降曲线与实测的曲线较为吻合，可作为确定大直径灌注长桩承载力的依据，经过对工程实例的计算与实测对比分析，证明该理论可靠、方法简单，且具有较好的适用性。

On Load-Settlement Relation of Long Large-diameter Cast-in-Situ Place Piles Under Negative Friction

The load transfer function taking account of negative friction is presented as the load transfer model of pile-side to simulate nonlinear behaviors of surrounding soil.The hyperbolic load transfer model is used for the pile end to simulate the nonlinear deformation properties of soil.And the Rusch model of concrete is introduced for considering the elastic-plastic characteristic of pile under heavy load.Furthermore,the Mindlin's solution is adopted to make the calculated settlement of a pile tally well with the practical value.Therefore,the analytical theory of load transfer for long large-diameter cast-in-place piles in layered ground is established,which can be used not only to calculate the settlement and bearing capacity of large-diameter piles in layer ground,but also to analyze the load transfer law of large-diameter piles in layered ground.The derived load-settlement curve agreed well with the testing results,thus it can be used in practice.