The Analysis On Bearing Capcity Of Uplift Pile Foundation

With the development of society, spaces for human activity are expandinggradually, industrial and civil buildings are also developing to underground andoffshore gradually, and anti-pull problem must be considered in design ofunderground and offshore structures. Pile foundation occupies a very importantposition in most types of uplift foundations. Compared with other uplift basis,theoretical research on tension piles is far behind the development of engineeringpractice, A large part of the research about tension pile is based on compressive piletheory at the moment, and it is not mature enough on theoretical solving methods ofuplift pile’s bearing capacity and principles of load transfer which is under upliftloads, so it lacks of systematic study on deformation characteristics and pile groupeffect of tension pile.Firstly, this paper summarized three kinds of failure mode on same-sectiontension pile foundation, and do some analysis on the advantages and disadvantagesand applicability of three Uplift Pile Capacity Calculation Theory (Chattopadhyaycomputing theory, the bearing capacity calculation theory of tension pile on layeredground and the "The technical specifications of pile foundation" theory) and onecalculation theory of pile group effect coefficient(Madhav theory), so as to do thegroundwork for verify the accuracy of the simulation results. Secondly, I simulatedthe test of single and group pile uplift capacity through the finite element softwareABAQUS, which was done by McCabe et al. in2006. By comparing the simulationresults and the experimental results, I find the result of bearing capacity anddeformation are coincided very well, so it verified the validity of the model. Againby simulating the uplift capacity variation of single pile with pile-soil frictioncoefficient, soil elastic modulus, pile diameter, pile length, etc., analyzed andsummarized the bearing capacity variation of single tension pile, and also studiedregular pattern of pile friction as well as the variation of axial force. Finally,simulated the process of uplift piles by ABAQUS finite element software, whichconsist of4groups of pile group (2,4,5,9) and one group of single pile, andstudied the uplift capacity variation of pile groups with pile diameter, the number of pile, then studied the group effect coefficient with the number of piles and pilelength variation, and also checked the simulation results of pile bearing capacity andcrack width which use the methods given by "The technical specifications of pilefoundation", and get some useful conclusions for engineering.