Self-balancing Testing Method For Bearing Capacity Of Pile Foundation And Numerical Simulation Study

The self-balancing testing method of bearing capacity of pile foundation is a newly developed one in recent years and it has the advantages of simple test device,large loading tonnage and high test accuracy.In this paper,the test of bearing capacity of Dongjin station in Hubei Xiangyang is taken as the entry point,and the self-balance test is carried out on the test pile.At the same time,the finite element analysis software MIDAS/GTSNX are used to simulate the test process and the influence of load cell location on bearing capacity and influence of pile top loading and self-balancing loading on ultimate bearing capacity.The main contents and work of this paper are as follows:(1)The function and development of the pile foundation and the bearing capacity detection technology of the pile foundation are elaborated;The research status of self-balancing detection method at home and abroad is briefly summarized.(2)The basic principle of the self-balancing detection method,the determination of the balance point position,the load-cell placement technology and the data conversion method are analyzed and studied.(3)Based on the test of the bearing capacity of three piles model in Dongjin Station,Hubei Province,the self-balance test was carried out on 3 piles model,and the specific matters such as preliminary preparation,on-site construction and post-test were elaborated.Through the test,the axial force and displacement values of the piles under different loads were measured,and the Q-s,s-lgt,s-lgQ were drawn.The lateral friction resistance and compression bearing capacity of the soil piles around the 3 test piles were calculated,and the compression bearing capacity of the 3 test piles met the design requirements,then measured lateral friction resistance of each soil layer in this area is given.(4)The finite element analysis software MIDAS/GTSNX was used to conduct numerical simulation of self-balancing test of test pile 2.The compression bearing capacity of the pile model 2 was verified by comparing the self-balancing test and numerical simulation data and the test conclusion of the force is not less than 28500.(5)Using the control variable method,under the same conditions as the original model,the position of the load-cell is changed,and the optimal load-cell placement position of the test is studied.It is more practical to use numerical calculation and theoretical calculation to determine the location of load cell.(6)The influence of pile top loading and self-balancing loading on ultimate bearing capacity is analyzed,and the general rules of ultimate bearing capacity of pile top loading and provide reference for similar experiment.