عنوان مقاله [English]
Determination of bearing capacity of piles is one of the important subjects which always challenge geotechnical engineers. The factors which affect the bearing capacity of a pile in compressive, tensile or lateral loading are
consisting of geometrical characteristics of pile such as length and shape of cross section, execution methods (cast in place, driving) and also geotechnical specifications. Due to these numerous factors, a direct estimation of pile baring capacity based on in-situ testing is the most precise and reliable method. However, this method is expensive, time consuming and troublesome .
In this regard, geotechnical engineers usually utilize the classic formulations proposed by some soil mechanics pioneers such as Meyerhof, Hansen, and Vesic to estimate the ultimate bearing capacity of piles. However, these relationships may lead to conservative or unsafe designs. Numerical methods, on the other hand, has been a powerful but relatively cheap approach which help engineers to obtain a reasonable estimate of ultimate bearing capacity based on existent soil mechanics parameters. Nevertheless, a wrong determination of
geomechanical parameters can lead to a wrong estimation of pile bearing capacity.
To overcome those difficulties, a combination of pile loading tests and numerical modeling is able to submit a precise and reasonable cost solution to the problem. In this method, the geometechnical parameters are varied in numerical modeling in such a way that the results of load-settlement curve obtained by a number of numerical analyses find a good agreement with the same curve recorded during in-situ pile test .
In this study, a suitable arrangement of all parameters affecting the numerical analysis is introduced based on Taguchi systematic method to allow a good agreement between the results of numerical analysis and pile load testing. Hereby, the accurate soil parameters and the relative importance of each factor which govern the bearing capacity are determined. In this research, the laboratory soil mechanics parameters and the results of pile load testing in a specific site are incorporated into a group of Taguchi analyses to improve the mechanical parameters of soil. The results indicated that the soil-pile interface factor, frictional angle and cohesion of soil are major factors in the bearing capacity, while Poissons ratio and dilation angle play minor roles.