Three-dimensional Non-linear Finite Element Analysis Of The Settlement Of Pile Group Foundation Composed Of Large-diameter And Super-long Piles

With the modern civil projects developing in the directions of super-height, super-weight and super-depth, the pile group foundation composed of the Large-diameter and super-long piles are adopted by more and more projects. But people' s understanding of the basic laws of this kind of large pile group foundation far lags behind the request for the engineering design , especially the study on the law of the settlement of the pile group foundation has been still far from perfect.Therefore, in this paper, after deeply studying the present calculation methods for the settlement of pile group foundation, based on the other research works, the three-dimensional non-linear finite element calculation technology is adopted to study the mechanism of the development of the settlement and the distribution of its settlement of the large-diameter super-long pile group foundation. Firstly , the calculation theory of the non-linear material and non-linear contact finite element method is expounded and the flow chart has been drawn. Secondly, the three-dimensional non-linear finite element method is adopted to simulate the process of the self-balanced loading test . By comparison and analysis of the result of the calculation of the finite element method and the data of the field self-balanced loading test, the mechanical parameters of the pile-soil interaction is acquired. Furthermore, with a project example , by the ANSYS, the three-dimensional simulation model have been founded , and then the corresponding program written by its APDL language has been developed to output the relevant information of the model into the code of the ABAQUS. And then, the problem of the settlement of the pile group foundation can be solved by the ABAQUS and the mechanism of the development of the settlement and the distribution of its settlement of the pile group foundation after loading and its variety while the distance between piles is expanded , are analyzed.Based on the application of the above calculation method, some conclusions can be drawn. Firstly , the problem of the settlement of the pile group foundation can be solved efficiently by the ABAQUS and the three-dimensional non-linear finite element method can be regarded as a good way to predict the settlement and optimize and examine the design. Secondly, utilizing the ANSYS to set up the simulation model and transfering the relevant information of the model into the code of the ABAQUS, is high-efficient. Thirdly, utilizing the method of the back analysis to acquire the mechanical parameters of pile-soil interaction is rational.Based on the result of the non-linear finite element analysis, some conclusions and suggestions are also proposed. Firstly, increasing thedistance between the piles can help to obviously reduce the settlement of the pile group foundation and raise the weight-bearing capability. Secondly,it is found that the soil under the cap among the piles bears a part of the load because of being compressed , so its functions should be considered during designing. Thirdly, consciously increasing the quantities of the boder piles and the corner piles and increasing the distance between the middle piles, can help to reduce the settlement of the pile group foundation.