Bearing Characteristics And Calculation Method Of Bearing Capacity Of Screw Cast-in-place Pile

Due to the existence of auger drill in the pile body,the bearing capacity of screw pile is obviously better than ordinary cast-in-place pile,which leading to control settlement effectively.Based on the same reason,the interaction between pile and soil is more complex,therefore,the theoretical research lags far behind the engineering application.In this paper,two kinds of failure modes of screw pile are given,the influence of different factors on its bearing capacity is compared,and the calculation method of bearing capacity is discussed.Then through static load test,the bearing characteristics of screw pile are researched in situ.Finally,the bearing characteristics of single screw pile and pile groups foundation are studied by ABAQUS software.The main work of this paper is as follows:(1)The research status of screw-shaped piles is summarized.The equipment,construction technology and construction steps of screw pile are briefly introduced.(2)The bearing mechanism of screw pile is analyzed theoretically.With different screw spacing,two kinds of failure modes of screw pile are introduced.The bearing capacity influent factors is analyzed,including screw parameters,compaction effect,expanding and pressure grouting technology.The main calculation methods of bearing capacity of screw pile are given and discussed.(3)In-situ test of bearing capacity of screw pile is carried out relying on a project.The influence on settlement and deformation is analyzed by a experiment,including pile diameter,pile length and soil properties around piles.The law of load transfer and mechanism are studied through engineering simulation.(4)Using ABAUQS software to establish the simulation model.The correctness of the model is proved by the comparing between experiment and simulation results.The factors,including pile length,screw spacing and screw segment ratio is further discussed.(5)Based on Q-s data and the nephograms of stress and displacement,pile group effect,resulted from pile spacing and pile length on pile group,is analyzed by ABAQUS.