A Study Of Subsidence Characteristics Of Single Pile Under Freezing-thawing Cycle Conditions

With the development of the West of China and the construction of Qingzang railway, pile foundations are applied extensively in frozen soil engineering in code region. The subsidence of pile foundations is the main and important aspect in pile foundation design and its characteristics are always many scholars' hotspot. The subsidence characteristics of single pile in cold region are studied and some conclusions are drawn with the method of theory study and computer simulation, based on the domestic and foreign scholars' study achievements in this field.On the basis of load transfer mechanism and destruction patterns of single pile, load transfer method and shearing deformation method for subsidence computing of single pile are mainly discussed. Considering the layer of soil mass and the change of body friction force of single pile, Cooke's shearing deformation method is discussed and is made to be tally with the actual situation. According to its mechanical characteristics, to further show the actual situation of interaction between pile and soil mass, different single pile subsidence computation models are built in seasonal frozen zone and permafrost zone. A computing example is given and analyzed. In the computer simulation of FEM software ANSYS, contact surface element is used. Its computation results are compared and analyzed with the results used theoretical computation method of this thesis. It shows that the tendencies of top subsidence of pile along with the change of thawing depth are mainly consistent in these two results and proves the rationality of theoretical computation method of this thesis. So, it provides reference in the design and construction of pile in practical engineering.