Abstract: This paper presents a method of estimating the ultimate bearing capacity of soils using the load-settlement curve. Four different data normalization methods are used in the data processing in order to discuss the effect of each method on the location of the curve inflection point. In addition, three methods that are used in the ultimate capacity estimation are investigated and the statistical characterization of each curve fitting method is also discussed. The results indicate that, the hyperbolic curve model can better fit the tested loadsettlement data. For a set of data, the ultimate bearing capacity values obtained by curve inflection method, settlement curve fitting method and parameter method are increasing. The best method is settlement curve fitting method. If the accurate location of the inflection point needs to be determined, the normalization of the tested data is necessary. Then, the curve fitting method can be applied. The probabilistic analysis shows that there are strong negative correlation between the two curve fitting parameters of hyperbolic model of loadsettlement curves.

Key words: Ultimate Bearing Capacity, Curve Fitting, Pile Foundation, Load Test, Load-Settlement Curve