Admittance Analysis Based On Dynamic Testing Of Pile

The previous researches about the mechanical impedance method for testing of foundation pile mostly only stay on the basis of low strain.The method of calculating the pile’s bearing capacity has been controversial because the hammering force is relatively small and even the industry tends to deny it.However,a large amount of engineering practice data shows that the admittance parameters and dynamic stiffness are closely related to the quality and bearing capacity of pile and it is not advisable to completely negate it.A certain relative displacement is generated between the pile and the soil because the impact force is large enough during the dynamic testing of pile,At this time,the soil around the pile has entered the plastic deformation stage and side resistance and end resistance have been fully stimulated.It is very valuable to explore the relationship between dynamic stiffness,related parameters of admittance curve and the bearing capacity under this background.This paper focuses on the relationship between related parameters of admittance and bearing capacity on the basis of dynamic testing of pile.It solves the problem of how to obtain a reliable admittance curve more comprehensively and overcomes the uncertainty of obtaining the admittance curve in the past;it explores obtaining stable admittance parameters related to bearing capacity based on the admittance curve,including the average geometric admittance and dynamic stiffness and determines the credible parameters that can be used for subsequent analysis.In addition,the traditional different calculation methods of dynamic stiffness and geometric admittance are compared and analyzed and specific calculation modes that can be used in engineering practice are obtained.Finally,the pile’s dynamic testing measured data under the same geological conditions,pile length and pile diameters of the same project are selected.The relationship between the dynamic stiffness,the fundamental frequency and the maximum impact force,and the relationship between the dynamic stiffness,the average value of geometric guidance and the measured bearing capacity are discussed based on the stable analysis parameters.The dynamic stiffness and the average value of geometric guidance are closely related to the bearing capacity of pile and the traditional mechanical impedance method can be used for auxiliary analysis of pile’s dynamic testing based on the research samples in this article.