To improve the dynamic response of tapered piles and its application theory

the Winkler model was adopted to simulate surrounding soil

and the frequency domain and time domain responses of longitudinal vibration velocity of the pile top were obtained with the pile vibration equation simplified by changing variable

in which the pile was assumed to be elastic with gradually varied diameter and its body was divided into non-equal-section parts. The variable control method was adopted to investigate the influence factors. Results showed that the calculation results of the proposed model were similar with those of the traditional simplified model when soil shear wave velocity was low. However

the difference between the proposed model and the traditional simplified model became more significant as the shear wave velocity increased. For three geometric feature parameters

calculations showed that pile length L mainly affected the signal intensity of pile bottom. The longer the pile length was

the lower the reflected signal peak was. The radius Rm and cone angle α mainly affected the position of curve in C area

and slightly affected the reflection signal of pile bottom. With the increase of the compressional velocity (elastic modulus)

the reflection signal of pile bottom and the amplitude of frequency response curve became more significant.