Dynamic Analysis And Experimental Study Of Vibratory Pile Driving

With the rapid development of the domestic building industry and the sustainingimprovement of the construction period and the requirements of environmental protectionin practical engineering, pile installation by vibratory driving has been increasinglywelcomed by the construction units owing to its unique advantages of high efficiency andlow pollution. Vibratory pile driving is widely used in the fields of pile foundation work.At present, the principle of vibratory pile driving is short of systemic researches whichhave been made by domestic scholars. The study on dynamic analysis of vibratory piledriving system is mostly based on single-degree-of-freedom linear damping vibrationmodel, but this model is too simple to reflect the processes of vibratory pile driving verywell. In addition, some key construction parameters selection also depends on too muchexperience during construction processes of vibratory pile driving. Therefore, theoreticalanalysis and experimental research for vibratory pile driving are thoroughly performed inthis paper.Firstly, the principle of vibratory pile driving was systematically researched in thepaper, a soft spring was proposed to instead of the linear spring in linear damping modelby integrating the nonlinear stress-strain relationship of soil. A nonlinear dynamic modelof vibratory pile driving was established to describe pile driving processes better, formingthe foundation for dynamic analysis.Then, according to the nonlinear dynamic model, the forced vibration of the vibratorypile driving system was researched by means of the method of multiple scales. The forcedprimary resonance and secondary resonance of the system were respectively researched.Amplitude-frequency characteristic for steady primary resonance and secondary resonanceof the vibratory pile driving system were analyzed. The effects of construction parameterson amplitude-frequency characteristics for primary resonance and secondary resonancewere discussed.Finally, in terms of the principle of vibratory pile driving, the testbed for vibratory piledriving was designed and builded. The experiments on different physical properties of soilhave were done by using the testbed for vibratory pile driving under the condition of thesame exciting force. The relationships among exciting frequency, relative density of soil,saturation of soil and efficiency of vibratory pile driving were researched.The conclusions obtained by dynamic analysis and experimental study of vibratory pile driving in the paper can provide references for theoretical research, field constructionparameter optimization and development of pile driving equipment.