针对工程中常用的双曲线荷载传递函数，以上海地区不同场地的7根有实测桩身轴力分布的试桩资料、12根无实测轴力分布的单桩静载荷试验以及上海青浦某场地75根工程桩试桩资料为基础，对荷载传递函数参数a、b取值进行统计分析，研究了在不同土层中桩基荷载传递参数的变异性．研究表明，参数a、b反分析所得的均值与实测值较为接近，a、b之间呈负相关．相比地基土的常规物理力学性质指标，荷载传递参数a和b的离散度较大．柯尔莫哥洛夫-斯米诺夫（Kolmogorov-Smirnov, K-S)检验的结果表明，参数a、b不拒绝正态分布．

The load-transfer method (t-z method) is easy to calculate and can be used in design practice. The most important thing of using the t-z method is the determination of the load-transfer parameters. The uncertainties of the two parameters in the hyperbolic load-transfer function of pile foundation were investigated. Data of seven static load tests with strain gauges, twelve static load tests without strain gauges together with 75 load tests at a single site in Shanghai were collected. Statistical analyses were conducted for both measured and back-calculated parameters for different soil layers. It was found that the uncertainties of the back-calculated values are close to those of the measured ones. The parameters a and b are negatively correlated. Compared with basic soil properties such as unit weight and shear strength parameters, the COVs of the load transfer parameters are greater. According to the Kolmogorov-Smirnov (K-S) test at a significance level of 5%, the normal distribution for both parameters can not be rejected.