一种确定导管架平台群桩p-y数据的方法

A method to determine p-y data of jacket platform pile group

导管架海洋平台群桩基础的桩头约束是一种弹性约束。针对具有弹性约束桩头的群桩,提出了一种利用非线性地基梁群桩模型,通过迭代计算确定导管架平台群桩p-y数据的方法。该方法首先依据单桩p-y曲线,利用具有弹性约束桩头的群桩模型,计算桩头在总荷载作用下的水平位移;再利用Poulos相互作用系数确定由于群桩相互作用引起的桩头附加水平位移,将总荷载作用下的桩头水平位移与桩头附加水平位移叠加后的结果作为迭代计算的初始桩头水平位移。然后,依据桩头荷载与初始桩头水平位移,通过对单桩p-y数据的标定,确定其修正系数Ym,进而得到与第1次计算对应的群桩p-y数据。在接下来的迭代计算中,利用每次更新后的Ym确定该次计算使用的群桩p-y数据,并据此由群桩计算模型计算桩头位移,通过对单桩p-y数据标定确定相应的Ym,直到第i次与第i-1次计算出的Ym(i)和Ym(i-1)之间相对误差小于允许误差为止。由于该方法考虑群桩效应的p-y数据,且借助具有弹性约束桩头的群桩模型进行分析,从而使计算结果能客观反映具有弹性约束桩头群桩之间的相互作用与变形特性。

The pile group head of jacket platforms is elastic constrained head.According to the elastic constrained head,a method to determine p-y data of jacket platform pile groups using the nonlinear foundation beam model of pile group is proposed.The lateral displacement of pile head is first determined using the pile group model with the elastic constrained head and p-y data of a single pile under total loads for the method.Additional lateral displacements due to pile group interactions are determined using Poulos’s interaction factors.The superposition result of above two calculations is taken as the initial lateral displacement of pile head of iterative calculations.The modified factor,Ym,of p-y data of the pile group associated with the first calculation is determined by calibrating p-y data of a single pile based on pile head loads and initial lateral displacement.For following calculations,p-y data of pile group associated with each iteration are determined using the updated Ym and then are used to determine the lateral displacement of pile group head and new Ym until the relative difference between Ym（i） and Ym（i-1） associate with the iterations i and i-1 is less than the tolerance.Because the method uses the p-y data considering pile group effects and the pile group model with the elastic constrained head to analyze the pile group interactions,results can objectively reflect interactions of jacket platform pile group and the deformation behavior of pile group with the elastic constrained head.