Research On Load Transfer Function Of Single Pile Foundation And Ultimate Bearing Capacity In Permafrost Region

Firstly this paper introduces the present research on the latest trends of permafrost and research results to make matting for the future research. Secondly introduces the current domestic and foreign research progress on the frozen soil and non-frozen soil of the pile foundation of the load transfer function, makes a comparison between frozen soil pile foundation and non-frozen soil pile foundation and draws the conclusion of the particularity of frozen soil pile foundation.This paper is based on the numerical simulation and indoor simulation experiment, With the complexity of the pile-permafrost system, so ignores some factors hard to grasp or some of the indecisive factors in the analytical process of the frozen soil pile foundation. So the applicability of the achievement has its limitation. But it should be regarded as an attempt of great significance. In fact, the engineering and the scientific community has made a lot of research about the non-frozen soil pile foundation of the load transfer function, got a large number of achivement, and made many theory and assumptions. These assumptions have been directly or indirectly verified in the engineering application, with its rationality proved. But due to the great differences between the soil’s physical properties and the mechanical properties,these differences limits the extensive application of the theory. At present people have not yet put forward a general and applicable load transfer function, and the same theory of load transfer function of a parameter in different working conditions are also different. So it is more difficult to get a universally applicable frozen soil pile foundation load transfer function.Because the frozen soil is a complex multiphase body composed of gas, liquid,solid, and ideal plastic ice inclusions.The multiphase led to the complexity of the study about permafrost, long-term. The physical properties and state of permafrost is assessed according to comprehensive consideration of the above four index.Permafrost has rheological and creep characteristics, in the model test all of these factors do exist, but in the calculating process these factors will be ignored, so the calculation results are inevitably different from the real results.In the practical engineering application, especially in seasonal frozen earth, pile-permafrost system is influenced by natural, each factors influencing each other restricts the related research.According to the model pile test data analysis results, a kind of pile foundation load transfer function is derived which applies to cold regions.In this paper, with the load transfer function derived from the paper as a starting point,for vertical load, the bearing capacity of the single pile, the way of calculating bearing capacity of the frozen soiled pile were summed. The last part of the thesis is devoted to simulation method of pile body, soil and interface of the system of pile and frozen soil, and the analysis process and method of finite element program ANSYS, and the mechanical models of the interaction of pile and frozen soil.In the post-processing of the simulation result, isoline, node analysis, path analysis of stress and strain roundly analyze the stress and strain status of pile and soil system for vertical loading piles, this finite element programs result and the test result tally well, so the validity of this method of finite element is confirmed.