根据泉州市区6根现场试验桩的实测资料,对PHC桩上拔荷载-桩顶位移曲线进行拟合分析.基于1stOpt操作平台,选用Leyenberg-Marquardt结合Universal Global Optimization-UGO的拟合方法,选用双曲线模型、幂函数模型和双曲线幂函数组合模型对6根现场试验桩的拟合.结果表明双曲线幂函数组合模型的拟合精度最高,相关系数R超过0.999 9,基于该数学模型的PHC桩上拔荷载的计算值与实测值的误差一般为-0.48%至0.55%;相对于试验报告给出的单桩竖向抗拔极限承载力为1 400kN,根据拟合曲线预测的结果均有不同程度的提高,最高达59.13%.%Based on the measured data of six field test piles in Quanzhou downtown area, the optimizing fit analysis was conducted on the pile cap displacement curve of up drag for PHC Pile. Through software platform lstOp, Levenberg- Marquardt was first combined with Universal Global Optimization- UGO as the fitting method; then the six field test piles were fitted by means of hyperbolic curve model, power function model and compound model of hyperbolic curve power function. The results showed that the fitting accuracy of compound model of hyperbolic curve power function was the highest, and all its correlation coefficient R was above 0.999 9. Besides, such model had a better fitting effect on the uplift of PHC Pile than that of hyperbolic curve model and power function model. Generally, the error of calculated value and measured value for up drag of PHC Pile grounded on the mathematic model was between- 0.48％ and 0.55％. Yet compared with the value 1 400kN of ultimate vertical uplift bearing capacity of a single pile from the test report, together with the predicted result according to the fitting curve, the result was more or less improved with the highest value 59.13％. Thus, the pile cap displacement curve of up drag for PHC Pile was fitted via the compound model of hyperbolic curve power function and the prediction was conducted on ultimate vertical uplift bearing capacity of a single pile, the result of which is relatively accurate and reliable.
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