Abstract: The “hammer-pile-soil” system is simplified in a proper way due to coupling phenomena in joint vibration of multi hammers, the dynamics model and electromechanical coupling equations of the two joint piling vibration hammers are established. On that basis, small parameter cycle average method is used to perform the approximate analysis of the motor load torque during the coupling process, through which the influence factors of motor load torque, balance equations and coupling degree expression are obtained and mechanism of coupling phenomena is revealed. Matlab/Simulink is used to set up the model and perform the mathematical simulation of the electromechanical coupling process to obtain the basic principle of the electromechanical coupling process in different motor speed, initial phase difference and soil parameters. At last, the validity of the mathematical model, theory deductions and simulation results are verified by piling experiments in practice. These conclusions provide theory guidance in planning a control strategy of electrical joint vibration; also provide reference for the “mechanical—electrical” composite joint style and the structure design of the mechanical joint.

Key words: Joint vibration of multi hammers, Motor load torque　Coupling degree expression, Simulation