Study On The Influence Of The Cross Section Of The Plate On The Pullout Failure Of The Concrete Expanded Pile

The concrete plates-expanded pile is a new kind of variable section pile after the expansion of the bottom pile,squeezed branch pile,the type of pile has abandoned the form of "branch" of the squeezed branch pile in the past,all of which are made up of enlarged section.A series of development has been made in the theoretical research and the practical pile forming technology,the main forming process of the pile is divided into the squeezed pile,the spin pile and the reamer pile,the effect of different pile forming technology is different,and at the same time,the cross section of the expanded disc is also different,so the stress characteristics and bearing capacity of different pile types may also be slightly different.At present,the research results of the concrete expanded pile are mainly aimed at expanding the number of disk,disk spacing,slope angle,cantilever diameter and so on,the main content of this paper is the difference between the bearing capacity and the stress of the concrete pile with different cross section formed by different pile forming technology under the vertical tension.In theoretical research,through the establishment of four groups of concrete under the same conditions of the pile model,and draw the corresponding displacement,stress and strain nephogram analysis and comparison.Based on the analysis of the simulation results of the section of concrete expanded pile formed by the cross section of the concrete expanded pile model and the actual pile forming technology in the finite element analysis,finding out the similarities and differences between them,so as to determine the availability of the calculation formula for the concrete pile with different cross section.On this basis,this paper designed four groups of different types of the concrete plates-expanded pile,non symmetrical pile,the line asymmetric pile,curve of end plate symmetric pile,angle of end plate symmetric pile.It will study on the failure condition of the small scale half section model pile test and compare with the ANSYS software theory.In the experimental study,this paper uses the 1:40 semi-section pile to test the undisturbed soil in the laboratory,and observe the damage of the soil and measure the load displacement of the pile.Compared with the whole pile test,the half pile model test has the advantages of the whole process of observation,the clear displacement of the pile.Comprehensive analysis of experimental and theoretical results,analysis of the difference between concrete expansion pile with different cross sections and advantages,puts forward the applicability and reliability of concrete expansion pile uplift bearing capacity calculation model,which lays the theoretical foundation for the follow-up study,the study of expanding pile concrete has been improved.