Abstract：The loadtransfer method (tz method) is easy to calculate and can be used in design practice. The most important thing of using the tz method is the determination of the loadtransfer parameters. The uncertainties of the two parameters in the hyperbolic loadtransfer 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 backcalculated parameters for different soil layers. It was found that the uncertainties of the backcalculated 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 KolmogorovSmirnov (KS) test at a significance level of 5%, the normal distribution for both parameters can not be rejected.
